1MYSQL(1) MySQL Database System MYSQL(1)
2
3
4
6 mysql - the MySQL command-line client
7
9 mysql [options] db_name
10
12 mysql is a simple SQL shell with input line editing capabilities. It
13 supports interactive and noninteractive use. When used interactively,
14 query results are presented in an ASCII-table format. When used
15 noninteractively (for example, as a filter), the result is presented in
16 tab-separated format. The output format can be changed using command
17 options.
18
19 If you have problems due to insufficient memory for large result sets,
20 use the --quick option. This forces mysql to retrieve results from the
21 server a row at a time rather than retrieving the entire result set and
22 buffering it in memory before displaying it. This is done by returning
23 the result set using the mysql_use_result() C API function in the
24 client/server library rather than mysql_store_result().
25
26 Note
27 Alternatively, MySQL Shell offers access to the X DevAPI. For
28 details, see MySQL Shell 8.0[1].
29
30 Using mysql is very easy. Invoke it from the prompt of your command
31 interpreter as follows:
32
33 mysql db_name
34
35 Or:
36
37 mysql --user=user_name --password db_name
38
39 In this case, you'll need to enter your password in response to the
40 prompt that mysql displays:
41
42 Enter password: your_password
43
44 Then type an SQL statement, end it with ;, \g, or \G and press Enter.
45
46 Typing Control+C interrupts the current statement if there is one, or
47 cancels any partial input line otherwise.
48
49 You can execute SQL statements in a script file (batch file) like this:
50
51 mysql db_name < script.sql > output.tab
52
53 On Unix, the mysql client logs statements executed interactively to a
54 history file. See the section called “MYSQL CLIENT LOGGING”.
55
57 mysql supports the following options, which can be specified on the
58 command line or in the [mysql] and [client] groups of an option file.
59 For information about option files used by MySQL programs, see
60 Section 4.2.2.2, “Using Option Files”.
61
62 • --help, -? Display a help message and exit.
63
64 • --auto-rehash Enable automatic rehashing. This option is on by
65 default, which enables database, table, and column name completion.
66 Use --disable-auto-rehash to disable rehashing. That causes mysql
67 to start faster, but you must issue the rehash command or its \#
68 shortcut if you want to use name completion.
69
70 To complete a name, enter the first part and press Tab. If the name
71 is unambiguous, mysql completes it. Otherwise, you can press Tab
72 again to see the possible names that begin with what you have typed
73 so far. Completion does not occur if there is no default database.
74
75 Note
76 This feature requires a MySQL client that is compiled with the
77 readline library. Typically, the readline library is not
78 available on Windows.
79
80 • --auto-vertical-output Cause result sets to be displayed vertically
81 if they are too wide for the current window, and using normal
82 tabular format otherwise. (This applies to statements terminated by
83 ; or \G.)
84
85 • --batch, -B Print results using tab as the column separator, with
86 each row on a new line. With this option, mysql does not use the
87 history file.
88
89 Batch mode results in nontabular output format and escaping of
90 special characters. Escaping may be disabled by using raw mode; see
91 the description for the --raw option.
92
93 • --binary-as-hex When this option is given, mysql displays binary
94 data using hexadecimal notation (0xvalue). This occurs whether the
95 overall output display format is tabular, vertical, HTML, or XML.
96
97 --binary-as-hex when enabled affects display of all binary strings,
98 including those returned by functions such as CHAR() and UNHEX().
99 The following example demonstrates this using the ASCII code for A
100 (65 decimal, 41 hexadecimal):
101
102 • --binary-as-hex disabled:
103
104 mysql> SELECT CHAR(0x41), UNHEX('41');
105 +------------+-------------+
106 | CHAR(0x41) | UNHEX('41') |
107 +------------+-------------+
108 | A | A |
109 +------------+-------------+
110
111 • --binary-as-hex enabled:
112
113 mysql> SELECT CHAR(0x41), UNHEX('41');
114 +------------------------+--------------------------+
115 | CHAR(0x41) | UNHEX('41') |
116 +------------------------+--------------------------+
117 | 0x41 | 0x41 |
118 +------------------------+--------------------------+
119
120 To write a binary string expression so that it displays as a
121 character string regardless of whether --binary-as-hex is enabled,
122 use these techniques:
123
124 • The CHAR() function has a USING charset clause:
125
126 mysql> SELECT CHAR(0x41 USING utf8mb4);
127 +--------------------------+
128 | CHAR(0x41 USING utf8mb4) |
129 +--------------------------+
130 | A |
131 +--------------------------+
132
133 • More generally, use CONVERT() to convert an expression to a
134 given character set:
135
136 mysql> SELECT CONVERT(UNHEX('41') USING utf8mb4);
137 +------------------------------------+
138 | CONVERT(UNHEX('41') USING utf8mb4) |
139 +------------------------------------+
140 | A |
141 +------------------------------------+
142
143 As of MySQL 8.0.19, when mysql operates in interactive mode, this
144 option is enabled by default. In addition, output from the status
145 (or \s) command includes this line when the option is enabled
146 implicitly or explicitly:
147
148 Binary data as: Hexadecimal
149
150 To disable hexadecimal notation, use --skip-binary-as-hex
151
152 • --binary-mode This option helps when processing mysqlbinlog output
153 that may contain BLOB values. By default, mysql translates \r\n in
154 statement strings to \n and interprets \0 as the statement
155 terminator. --binary-mode disables both features. It also disables
156 all mysql commands except charset and delimiter in noninteractive
157 mode (for input piped to mysql or loaded using the source command).
158
159 • --bind-address=ip_address On a computer having multiple network
160 interfaces, use this option to select which interface to use for
161 connecting to the MySQL server.
162
163 • --character-sets-dir=dir_name The directory where character sets
164 are installed. See Section 10.15, “Character Set Configuration”.
165
166 • --column-names Write column names in results.
167
168 • --column-type-info Display result set metadata. This information
169 corresponds to the contents of C API MYSQL_FIELD data structures.
170 See C API Basic Data Structures[2].
171
172 • --comments, -c Whether to strip or preserve comments in statements
173 sent to the server. The default is --skip-comments (strip
174 comments), enable with --comments (preserve comments).
175
176 Note
177 The mysql client always passes optimizer hints to the server,
178 regardless of whether this option is given.
179
180 Comment stripping is deprecated. Expect this feature and the
181 options to control it to be removed in a future MySQL release.
182
183 • --compress, -C Compress all information sent between the client and
184 the server if possible. See Section 4.2.8, “Connection Compression
185 Control”.
186
187 As of MySQL 8.0.18, this option is deprecated. Expect it to be
188 removed in a future version of MySQL. See the section called
189 “Configuring Legacy Connection Compression”.
190
191 • --compression-algorithms=value The permitted compression algorithms
192 for connections to the server. The available algorithms are the
193 same as for the protocol_compression_algorithms system variable.
194 The default value is uncompressed.
195
196 For more information, see Section 4.2.8, “Connection Compression
197 Control”.
198
199 This option was added in MySQL 8.0.18.
200
201 • --connect-expired-password Indicate to the server that the client
202 can handle sandbox mode if the account used to connect has an
203 expired password. This can be useful for noninteractive invocations
204 of mysql because normally the server disconnects noninteractive
205 clients that attempt to connect using an account with an expired
206 password. (See Section 6.2.16, “Server Handling of Expired
207 Passwords”.)
208
209 • --connect-timeout=value The number of seconds before connection
210 timeout. (Default value is 0.)
211
212 • --database=db_name, -D db_name The database to use. This is useful
213 primarily in an option file.
214
215 • --debug[=debug_options], -# [debug_options] Write a debugging log.
216 A typical debug_options string is d:t:o,file_name. The default is
217 d:t:o,/tmp/mysql.trace.
218
219 This option is available only if MySQL was built using WITH_DEBUG.
220 MySQL release binaries provided by Oracle are not built using this
221 option.
222
223 • --debug-check Print some debugging information when the program
224 exits.
225
226 This option is available only if MySQL was built using WITH_DEBUG.
227 MySQL release binaries provided by Oracle are not built using this
228 option.
229
230 • --debug-info, -T Print debugging information and memory and CPU
231 usage statistics when the program exits.
232
233 This option is available only if MySQL was built using WITH_DEBUG.
234 MySQL release binaries provided by Oracle are not built using this
235 option.
236
237 • --default-auth=plugin A hint about which client-side authentication
238 plugin to use. See Section 6.2.17, “Pluggable Authentication”.
239
240 • --default-character-set=charset_name Use charset_name as the
241 default character set for the client and connection.
242
243 This option can be useful if the operating system uses one
244 character set and the mysql client by default uses another. In this
245 case, output may be formatted incorrectly. You can usually fix such
246 issues by using this option to force the client to use the system
247 character set instead.
248
249 For more information, see Section 10.4, “Connection Character Sets
250 and Collations”, and Section 10.15, “Character Set Configuration”.
251
252 • --defaults-extra-file=file_name Read this option file after the
253 global option file but (on Unix) before the user option file. If
254 the file does not exist or is otherwise inaccessible, an error
255 occurs. If file_name is not an absolute path name, it is
256 interpreted relative to the current directory.
257
258 For additional information about this and other option-file
259 options, see Section 4.2.2.3, “Command-Line Options that Affect
260 Option-File Handling”.
261
262 • --defaults-file=file_name Use only the given option file. If the
263 file does not exist or is otherwise inaccessible, an error occurs.
264 If file_name is not an absolute path name, it is interpreted
265 relative to the current directory.
266
267 Exception: Even with --defaults-file, client programs read
268 .mylogin.cnf.
269
270 For additional information about this and other option-file
271 options, see Section 4.2.2.3, “Command-Line Options that Affect
272 Option-File Handling”.
273
274 • --defaults-group-suffix=str Read not only the usual option groups,
275 but also groups with the usual names and a suffix of str. For
276 example, mysql normally reads the [client] and [mysql] groups. If
277 this option is given as --defaults-group-suffix=_other, mysql also
278 reads the [client_other] and [mysql_other] groups.
279
280 For additional information about this and other option-file
281 options, see Section 4.2.2.3, “Command-Line Options that Affect
282 Option-File Handling”.
283
284 • --delimiter=str Set the statement delimiter. The default is the
285 semicolon character (;).
286
287 • --disable-named-commands Disable named commands. Use the \* form
288 only, or use named commands only at the beginning of a line ending
289 with a semicolon (;). mysql starts with this option enabled by
290 default. However, even with this option, long-format commands still
291 work from the first line. See the section called “MYSQL CLIENT
292 COMMANDS”.
293
294 • --dns-srv-name=name Specifies the name of a DNS SRV record that
295 determines the candidate hosts to use for establishing a connection
296 to a MySQL server. For information about DNS SRV support in MySQL,
297 see Section 4.2.6, “Connecting to the Server Using DNS SRV
298 Records”.
299
300 Suppose that DNS is configured with this SRV information for the
301 example.com domain:
302
303 Name TTL Class Priority Weight Port Target
304 _mysql._tcp.example.com. 86400 IN SRV 0 5 3306 host1.example.com
305 _mysql._tcp.example.com. 86400 IN SRV 0 10 3306 host2.example.com
306 _mysql._tcp.example.com. 86400 IN SRV 10 5 3306 host3.example.com
307 _mysql._tcp.example.com. 86400 IN SRV 20 5 3306 host4.example.com
308
309 To use that DNS SRV record, invoke mysql like this:
310
311 mysql --dns-srv-name=_mysql._tcp.example.com
312
313 mysql then attempts a connection to each server in the group until
314 a successful connection is established. A failure to connect occurs
315 only if a connection cannot be established to any of the servers.
316 The priority and weight values in the DNS SRV record determine the
317 order in which servers should be tried.
318
319 When invoked with --dns-srv-name, mysql attempts to establish TCP
320 connections only.
321
322 The --dns-srv-name option takes precedence over the --host option
323 if both are given. --dns-srv-name causes connection establishment
324 to use the mysql_real_connect_dns_srv() C API function rather than
325 mysql_real_connect(). However, if the connect command is
326 subsequently used at runtime and specifies a host name argument,
327 that host name takes precedence over any --dns-srv-name option
328 given at mysql startup to specify a DNS SRV record.
329
330 This option was added in MySQL 8.0.22.
331
332 • --enable-cleartext-plugin Enable the mysql_clear_password cleartext
333 authentication plugin. (See Section 6.4.1.4, “Client-Side Cleartext
334 Pluggable Authentication”.)
335
336 • --execute=statement, -e statement Execute the statement and quit.
337 The default output format is like that produced with --batch. See
338 Section 4.2.2.1, “Using Options on the Command Line”, for some
339 examples. With this option, mysql does not use the history file.
340
341 • --fido-register-factor=value The factor or factors for which FIDO
342 device registration must be performed. This option value must be a
343 single value, or two values separated by commas. Each value must be
344 2 or 3, so the permitted option values are '2', '3', '2,3' and
345 '3,2'.
346
347 For example, an account that requires registration for a 3rd
348 authentication factor invokes the mysql client as follows:
349
350 mysql --user=user_name --fido-register-factor=3
351
352 An account that requires registration for a 2nd and 3rd
353 authentication factor invokes the mysql client as follows:
354
355 mysql --user=user_name --fido-register-factor=2,3
356
357 If registration is successful, a connection is established. If
358 there is an authentication factor with a pending registration, a
359 connection is placed into pending registration mode when attempting
360 to connect to the server. In this case, disconnect and reconnect
361 with the correct --fido-register-factor value to complete the
362 registration.
363
364 Registration is a two step process comprising initiate registration
365 and finish registration steps. The initiate registration step
366 executes this statement:
367
368 ALTER USER user factor INITIATE REGISTRATION
369
370 The statement returns a result set containing a 32 byte challenge,
371 the user name, and the relying party ID (see
372 authentication_fido_rp_id).
373
374 The finish registration step executes this statement:
375
376 ALTER USER user factor FINISH REGISTRATION SET CHALLENGE_RESPONSE AS 'auth_string'
377
378 The statement completes the registration and sends the following
379 information to the server as part of the auth_string: authenticator
380 data, an optional attestation certificate in X.509 format, and a
381 signature.
382
383 The initiate and registration steps must be performed in a single
384 connection, as the challenge received by the client during the
385 initiate step is saved to the client connection handler.
386 Registration would fail if the registration step was performed by a
387 different connection. The --fido-register-factor option executes
388 both the initiate and registration steps, which avoids the failure
389 scenario described above and prevents having to execute the ALTER
390 USER initiate and registration statements manually.
391
392 The --fido-register-factor option is only available for the mysql
393 client and MySQL Shell. Other MySQL client programs do not support
394 it.
395
396 For related information, see the section called “Using FIDO
397 Authentication”.
398
399 • --force, -f Continue even if an SQL error occurs.
400
401 • --get-server-public-key Request from the server the public key
402 required for RSA key pair-based password exchange. This option
403 applies to clients that authenticate with the caching_sha2_password
404 authentication plugin. For that plugin, the server does not send
405 the public key unless requested. This option is ignored for
406 accounts that do not authenticate with that plugin. It is also
407 ignored if RSA-based password exchange is not used, as is the case
408 when the client connects to the server using a secure connection.
409
410 If --server-public-key-path=file_name is given and specifies a
411 valid public key file, it takes precedence over
412 --get-server-public-key.
413
414 For information about the caching_sha2_password plugin, see
415 Section 6.4.1.2, “Caching SHA-2 Pluggable Authentication”.
416
417 • --histignore A list of one or more colon-separated patterns
418 specifying statements to ignore for logging purposes. These
419 patterns are added to the default pattern list
420 ("*IDENTIFIED*:*PASSWORD*"). The value specified for this option
421 affects logging of statements written to the history file, and to
422 syslog if the --syslog option is given. For more information, see
423 the section called “MYSQL CLIENT LOGGING”.
424
425 • --host=host_name, -h host_name Connect to the MySQL server on the
426 given host.
427
428 The --dns-srv-name option takes precedence over the --host option
429 if both are given. --dns-srv-name causes connection establishment
430 to use the mysql_real_connect_dns_srv() C API function rather than
431 mysql_real_connect(). However, if the connect command is
432 subsequently used at runtime and specifies a host name argument,
433 that host name takes precedence over any --dns-srv-name option
434 given at mysql startup to specify a DNS SRV record.
435
436 • --html, -H Produce HTML output.
437
438 • --ignore-spaces, -i Ignore spaces after function names. The effect
439 of this is described in the discussion for the IGNORE_SPACE SQL
440 mode (see Section 5.1.11, “Server SQL Modes”).
441
442 • --init-command=str SQL statement to execute after connecting to the
443 server. If auto-reconnect is enabled, the statement is executed
444 again after reconnection occurs.
445
446 • --line-numbers Write line numbers for errors. Disable this with
447 --skip-line-numbers.
448
449 • --load-data-local-dir=dir_name This option affects the client-side
450 LOCAL capability for LOAD DATA operations. It specifies the
451 directory in which files named in LOAD DATA LOCAL statements must
452 be located. The effect of --load-data-local-dir depends on whether
453 LOCAL data loading is enabled or disabled:
454
455 • If LOCAL data loading is enabled, either by default in the
456 MySQL client library or by specifying --local-infile[=1], the
457 --load-data-local-dir option is ignored.
458
459 • If LOCAL data loading is disabled, either by default in the
460 MySQL client library or by specifying --local-infile=0, the
461 --load-data-local-dir option applies.
462
463 When --load-data-local-dir applies, the option value designates the
464 directory in which local data files must be located. Comparison of
465 the directory path name and the path name of files to be loaded is
466 case-sensitive regardless of the case sensitivity of the underlying
467 file system. If the option value is the empty string, it names no
468 directory, with the result that no files are permitted for local
469 data loading.
470
471 For example, to explicitly disable local data loading except for
472 files located in the /my/local/data directory, invoke mysql like
473 this:
474
475 mysql --local-infile=0 --load-data-local-dir=/my/local/data
476
477 When both --local-infile and --load-data-local-dir are given, the
478 order in which they are given does not matter.
479
480 Successful use of LOCAL load operations within mysql also requires
481 that the server permits local loading; see Section 6.1.6, “Security
482 Considerations for LOAD DATA LOCAL”
483
484 The --load-data-local-dir option was added in MySQL 8.0.21.
485
486 • --local-infile[={0|1}] By default, LOCAL capability for LOAD DATA
487 is determined by the default compiled into the MySQL client
488 library. To enable or disable LOCAL data loading explicitly, use
489 the --local-infile option. When given with no value, the option
490 enables LOCAL data loading. When given as --local-infile=0 or
491 --local-infile=1, the option disables or enables LOCAL data
492 loading.
493
494 If LOCAL capability is disabled, the --load-data-local-dir option
495 can be used to permit restricted local loading of files located in
496 a designated directory.
497
498 Successful use of LOCAL load operations within mysql also requires
499 that the server permits local loading; see Section 6.1.6, “Security
500 Considerations for LOAD DATA LOCAL”
501
502 • --login-path=name Read options from the named login path in the
503 .mylogin.cnf login path file. A “login path” is an option group
504 containing options that specify which MySQL server to connect to
505 and which account to authenticate as. To create or modify a login
506 path file, use the mysql_config_editor utility. See
507 mysql_config_editor(1).
508
509 For additional information about this and other option-file
510 options, see Section 4.2.2.3, “Command-Line Options that Affect
511 Option-File Handling”.
512
513 • --max-allowed-packet=value The maximum size of the buffer for
514 client/server communication. The default is 16MB, the maximum is
515 1GB.
516
517 • --max-join-size=value The automatic limit for rows in a join when
518 using --safe-updates. (Default value is 1,000,000.)
519
520 • --named-commands, -G Enable named mysql commands. Long-format
521 commands are permitted, not just short-format commands. For
522 example, quit and \q both are recognized. Use --skip-named-commands
523 to disable named commands. See the section called “MYSQL CLIENT
524 COMMANDS”.
525
526 • --net-buffer-length=value The buffer size for TCP/IP and socket
527 communication. (Default value is 16KB.)
528
529 • --network-namespace=name The network namespace to use for TCP/IP
530 connections. If omitted, the connection uses the default (global)
531 namespace. For information about network namespaces, see
532 Section 5.1.14, “Network Namespace Support”.
533
534 This option was added in MySQL 8.0.22. It is available only on
535 platforms that implement network namespace support.
536
537 • --no-auto-rehash, -A This has the same effect as
538 --skip-auto-rehash. See the description for --auto-rehash.
539
540 • --no-beep, -b Do not beep when errors occur.
541
542 • --no-defaults Do not read any option files. If program startup
543 fails due to reading unknown options from an option file,
544 --no-defaults can be used to prevent them from being read.
545
546 The exception is that the .mylogin.cnf file is read in all cases,
547 if it exists. This permits passwords to be specified in a safer way
548 than on the command line even when --no-defaults is used. To create
549 .mylogin.cnf, use the mysql_config_editor utility. See
550 mysql_config_editor(1).
551
552 For additional information about this and other option-file
553 options, see Section 4.2.2.3, “Command-Line Options that Affect
554 Option-File Handling”.
555
556 • --one-database, -o Ignore statements except those that occur while
557 the default database is the one named on the command line. This
558 option is rudimentary and should be used with care. Statement
559 filtering is based only on USE statements.
560
561 Initially, mysql executes statements in the input because
562 specifying a database db_name on the command line is equivalent to
563 inserting USE db_name at the beginning of the input. Then, for each
564 USE statement encountered, mysql accepts or rejects following
565 statements depending on whether the database named is the one on
566 the command line. The content of the statements is immaterial.
567
568 Suppose that mysql is invoked to process this set of statements:
569
570 DELETE FROM db2.t2;
571 USE db2;
572 DROP TABLE db1.t1;
573 CREATE TABLE db1.t1 (i INT);
574 USE db1;
575 INSERT INTO t1 (i) VALUES(1);
576 CREATE TABLE db2.t1 (j INT);
577
578 If the command line is mysql --force --one-database db1, mysql
579 handles the input as follows:
580
581 • The DELETE statement is executed because the default database
582 is db1, even though the statement names a table in a different
583 database.
584
585 • The DROP TABLE and CREATE TABLE statements are not executed
586 because the default database is not db1, even though the
587 statements name a table in db1.
588
589 • The INSERT and CREATE TABLE statements are executed because the
590 default database is db1, even though the CREATE TABLE statement
591 names a table in a different database.
592
593 • --pager[=command] Use the given command for paging query output. If
594 the command is omitted, the default pager is the value of your
595 PAGER environment variable. Valid pagers are less, more, cat [>
596 filename], and so forth. This option works only on Unix and only in
597 interactive mode. To disable paging, use --skip-pager. the section
598 called “MYSQL CLIENT COMMANDS”, discusses output paging further.
599
600 • --password[=password], -p[password] The password of the MySQL
601 account used for connecting to the server. The password value is
602 optional. If not given, mysql prompts for one. If given, there must
603 be no space between --password= or -p and the password following
604 it. If no password option is specified, the default is to send no
605 password.
606
607 Specifying a password on the command line should be considered
608 insecure. To avoid giving the password on the command line, use an
609 option file. See Section 6.1.2.1, “End-User Guidelines for Password
610 Security”.
611
612 To explicitly specify that there is no password and that mysql
613 should not prompt for one, use the --skip-password option.
614
615 • --password1[=pass_val] The password for multifactor authentication
616 factor 1 of the MySQL account used for connecting to the server.
617 The password value is optional. If not given, mysql prompts for
618 one. If given, there must be no space between --password1= and the
619 password following it. If no password option is specified, the
620 default is to send no password.
621
622 Specifying a password on the command line should be considered
623 insecure. To avoid giving the password on the command line, use an
624 option file. See Section 6.1.2.1, “End-User Guidelines for Password
625 Security”.
626
627 To explicitly specify that there is no password and that mysql
628 should not prompt for one, use the --skip-password1 option.
629
630 --password1 and --password are synonymous, as are --skip-password1
631 and --skip-password.
632
633 • --password2[=pass_val] The password for multifactor authentication
634 factor 2 of the MySQL account used for connecting to the server.
635 The semantics of this option are similar to the semantics for
636 --password1; see the description of that option for details.
637
638 • --password3[=pass_val] The password for multifactor authentication
639 factor 3 of the MySQL account used for connecting to the server.
640 The semantics of this option are similar to the semantics for
641 --password1; see the description of that option for details.
642
643 • --pipe, -W On Windows, connect to the server using a named pipe.
644 This option applies only if the server was started with the
645 named_pipe system variable enabled to support named-pipe
646 connections. In addition, the user making the connection must be a
647 member of the Windows group specified by the
648 named_pipe_full_access_group system variable.
649
650 • --plugin-authentication-kerberos-client-mode=value On Windows, the
651 authentication_kerberos_client authentication plugin supports this
652 plugin option. It provides two possible values that the client user
653 can set at runtime: SSPI and GSSAPI.
654
655 The default value for the client-side plugin option uses Security
656 Support Provider Interface (SSPI), which is capable of acquiring
657 credentials from the Windows in-memory cache. Alternatively, the
658 client user can select a mode that supports Generic Security
659 Service Application Program Interface (GSSAPI) through the MIT
660 Kerberos library on Windows. GSSAPI is capable of acquiring cached
661 credentials previously generated by using the kinit command.
662
663 For more information, see Commands for Windows Clients in GSSAPI
664 Mode.
665
666 • --plugin-dir=dir_name The directory in which to look for plugins.
667 Specify this option if the --default-auth option is used to specify
668 an authentication plugin but mysql does not find it. See
669 Section 6.2.17, “Pluggable Authentication”.
670
671 • --port=port_num, -P port_num For TCP/IP connections, the port
672 number to use.
673
674 • --print-defaults Print the program name and all options that it
675 gets from option files.
676
677 For additional information about this and other option-file
678 options, see Section 4.2.2.3, “Command-Line Options that Affect
679 Option-File Handling”.
680
681 • --prompt=format_str Set the prompt to the specified format. The
682 default is mysql>. The special sequences that the prompt can
683 contain are described in the section called “MYSQL CLIENT
684 COMMANDS”.
685
686 • --protocol={TCP|SOCKET|PIPE|MEMORY} The transport protocol to use
687 for connecting to the server. It is useful when the other
688 connection parameters normally result in use of a protocol other
689 than the one you want. For details on the permissible values, see
690 Section 4.2.7, “Connection Transport Protocols”.
691
692 • --quick, -q Do not cache each query result, print each row as it is
693 received. This may slow down the server if the output is suspended.
694 With this option, mysql does not use the history file.
695
696 • --raw, -r For tabular output, the “boxing” around columns enables
697 one column value to be distinguished from another. For nontabular
698 output (such as is produced in batch mode or when the --batch or
699 --silent option is given), special characters are escaped in the
700 output so they can be identified easily. Newline, tab, NUL, and
701 backslash are written as \n, \t, \0, and \\. The --raw option
702 disables this character escaping.
703
704 The following example demonstrates tabular versus nontabular output
705 and the use of raw mode to disable escaping:
706
707 % mysql
708 mysql> SELECT CHAR(92);
709 +----------+
710 | CHAR(92) |
711 +----------+
712 | \ |
713 +----------+
714 % mysql -s
715 mysql> SELECT CHAR(92);
716 CHAR(92)
717 \\
718 % mysql -s -r
719 mysql> SELECT CHAR(92);
720 CHAR(92)
721 \
722
723 • --reconnect If the connection to the server is lost, automatically
724 try to reconnect. A single reconnect attempt is made each time the
725 connection is lost. To suppress reconnection behavior, use
726 --skip-reconnect.
727
728 • --safe-updates, --i-am-a-dummy, -U If this option is enabled,
729 UPDATE and DELETE statements that do not use a key in the WHERE
730 clause or a LIMIT clause produce an error. In addition,
731 restrictions are placed on SELECT statements that produce (or are
732 estimated to produce) very large result sets. If you have set this
733 option in an option file, you can use --skip-safe-updates on the
734 command line to override it. For more information about this
735 option, see Using Safe-Updates Mode (--safe-updates).
736
737 • --select-limit=value The automatic limit for SELECT statements when
738 using --safe-updates. (Default value is 1,000.)
739
740 • --server-public-key-path=file_name The path name to a file in PEM
741 format containing a client-side copy of the public key required by
742 the server for RSA key pair-based password exchange. This option
743 applies to clients that authenticate with the sha256_password or
744 caching_sha2_password authentication plugin. This option is ignored
745 for accounts that do not authenticate with one of those plugins. It
746 is also ignored if RSA-based password exchange is not used, as is
747 the case when the client connects to the server using a secure
748 connection.
749
750 If --server-public-key-path=file_name is given and specifies a
751 valid public key file, it takes precedence over
752 --get-server-public-key.
753
754 For sha256_password, this option applies only if MySQL was built
755 using OpenSSL.
756
757 For information about the sha256_password and caching_sha2_password
758 plugins, see Section 6.4.1.3, “SHA-256 Pluggable Authentication”,
759 and Section 6.4.1.2, “Caching SHA-2 Pluggable Authentication”.
760
761 • --shared-memory-base-name=name On Windows, the shared-memory name
762 to use for connections made using shared memory to a local server.
763 The default value is MYSQL. The shared-memory name is
764 case-sensitive.
765
766 This option applies only if the server was started with the
767 shared_memory system variable enabled to support shared-memory
768 connections.
769
770 • --show-warnings Cause warnings to be shown after each statement if
771 there are any. This option applies to interactive and batch mode.
772
773 • --sigint-ignore Ignore SIGINT signals (typically the result of
774 typing Control+C).
775
776 Without this option, typing Control+C interrupts the current
777 statement if there is one, or cancels any partial input line
778 otherwise.
779
780 • --silent, -s Silent mode. Produce less output. This option can be
781 given multiple times to produce less and less output.
782
783 This option results in nontabular output format and escaping of
784 special characters. Escaping may be disabled by using raw mode; see
785 the description for the --raw option.
786
787 • --skip-column-names, -N Do not write column names in results.
788
789 • --skip-line-numbers, -L Do not write line numbers for errors.
790 Useful when you want to compare result files that include error
791 messages.
792
793 • --socket=path, -S path For connections to localhost, the Unix
794 socket file to use, or, on Windows, the name of the named pipe to
795 use.
796
797 On Windows, this option applies only if the server was started with
798 the named_pipe system variable enabled to support named-pipe
799 connections. In addition, the user making the connection must be a
800 member of the Windows group specified by the
801 named_pipe_full_access_group system variable.
802
803 • --ssl* Options that begin with --ssl specify whether to connect to
804 the server using encryption and indicate where to find SSL keys and
805 certificates. See the section called “Command Options for Encrypted
806 Connections”.
807
808 • --ssl-fips-mode={OFF|ON|STRICT} Controls whether to enable FIPS
809 mode on the client side. The --ssl-fips-mode option differs from
810 other --ssl-xxx options in that it is not used to establish
811 encrypted connections, but rather to affect which cryptographic
812 operations to permit. See Section 6.8, “FIPS Support”.
813
814 These --ssl-fips-mode values are permitted:
815
816 • OFF: Disable FIPS mode.
817
818 • ON: Enable FIPS mode.
819
820 • STRICT: Enable “strict” FIPS mode.
821
822
823 Note
824 If the OpenSSL FIPS Object Module is not available, the only
825 permitted value for --ssl-fips-mode is OFF. In this case,
826 setting --ssl-fips-mode to ON or STRICT causes the client to
827 produce a warning at startup and to operate in non-FIPS mode.
828 As of MySQL 8.0.34, this option is deprecated. Expect it to be
829 removed in a future version of MySQL.
830
831 • --syslog, -j This option causes mysql to send interactive
832 statements to the system logging facility. On Unix, this is syslog;
833 on Windows, it is the Windows Event Log. The destination where
834 logged messages appear is system dependent. On Linux, the
835 destination is often the /var/log/messages file.
836
837 Here is a sample of output generated on Linux by using --syslog.
838 This output is formatted for readability; each logged message
839 actually takes a single line.
840
841 Mar 7 12:39:25 myhost MysqlClient[20824]:
842 SYSTEM_USER:'oscar', MYSQL_USER:'my_oscar', CONNECTION_ID:23,
843 DB_SERVER:'127.0.0.1', DB:'--', QUERY:'USE test;'
844 Mar 7 12:39:28 myhost MysqlClient[20824]:
845 SYSTEM_USER:'oscar', MYSQL_USER:'my_oscar', CONNECTION_ID:23,
846 DB_SERVER:'127.0.0.1', DB:'test', QUERY:'SHOW TABLES;'
847
848 For more information, see the section called “MYSQL CLIENT
849 LOGGING”.
850
851 • --table, -t Display output in table format. This is the default for
852 interactive use, but can be used to produce table output in batch
853 mode.
854
855 • --tee=file_name Append a copy of output to the given file. This
856 option works only in interactive mode. the section called “MYSQL
857 CLIENT COMMANDS”, discusses tee files further.
858
859 • --tls-ciphersuites=ciphersuite_list The permissible ciphersuites
860 for encrypted connections that use TLSv1.3. The value is a list of
861 one or more colon-separated ciphersuite names. The ciphersuites
862 that can be named for this option depend on the SSL library used to
863 compile MySQL. For details, see Section 6.3.2, “Encrypted
864 Connection TLS Protocols and Ciphers”.
865
866 This option was added in MySQL 8.0.16.
867
868 • --tls-version=protocol_list The permissible TLS protocols for
869 encrypted connections. The value is a list of one or more
870 comma-separated protocol names. The protocols that can be named for
871 this option depend on the SSL library used to compile MySQL. For
872 details, see Section 6.3.2, “Encrypted Connection TLS Protocols and
873 Ciphers”.
874
875 • --unbuffered, -n Flush the buffer after each query.
876
877 • --user=user_name, -u user_name The user name of the MySQL account
878 to use for connecting to the server.
879
880 • --verbose, -v Verbose mode. Produce more output about what the
881 program does. This option can be given multiple times to produce
882 more and more output. (For example, -v -v -v produces table output
883 format even in batch mode.)
884
885 • --version, -V Display version information and exit.
886
887 • --vertical, -E Print query output rows vertically (one line per
888 column value). Without this option, you can specify vertical output
889 for individual statements by terminating them with \G.
890
891 • --wait, -w If the connection cannot be established, wait and retry
892 instead of aborting.
893
894 • --xml, -X Produce XML output.
895
896 <field name="column_name">NULL</field>
897
898 The output when --xml is used with mysql matches that of mysqldump
899 --xml. See mysqldump(1), for details.
900
901 The XML output also uses an XML namespace, as shown here:
902
903 $> mysql --xml -uroot -e "SHOW VARIABLES LIKE 'version%'"
904 <?xml version="1.0"?>
905 <resultset statement="SHOW VARIABLES LIKE 'version%'" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
906 <row>
907 <field name="Variable_name">version</field>
908 <field name="Value">5.0.40-debug</field>
909 </row>
910 <row>
911 <field name="Variable_name">version_comment</field>
912 <field name="Value">Source distribution</field>
913 </row>
914 <row>
915 <field name="Variable_name">version_compile_machine</field>
916 <field name="Value">i686</field>
917 </row>
918 <row>
919 <field name="Variable_name">version_compile_os</field>
920 <field name="Value">suse-linux-gnu</field>
921 </row>
922 </resultset>
923
924 • --zstd-compression-level=level The compression level to use for
925 connections to the server that use the zstd compression algorithm.
926 The permitted levels are from 1 to 22, with larger values
927 indicating increasing levels of compression. The default zstd
928 compression level is 3. The compression level setting has no effect
929 on connections that do not use zstd compression.
930
931 For more information, see Section 4.2.8, “Connection Compression
932 Control”.
933
934 This option was added in MySQL 8.0.18.
935
937 mysql sends each SQL statement that you issue to the server to be
938 executed. There is also a set of commands that mysql itself interprets.
939 For a list of these commands, type help or \h at the mysql> prompt:
940
941 mysql> help
942 List of all MySQL commands:
943 Note that all text commands must be first on line and end with ';'
944 ? (\?) Synonym for `help'.
945 clear (\c) Clear the current input statement.
946 connect (\r) Reconnect to the server. Optional arguments are db and host.
947 delimiter (\d) Set statement delimiter.
948 edit (\e) Edit command with $EDITOR.
949 ego (\G) Send command to mysql server, display result vertically.
950 exit (\q) Exit mysql. Same as quit.
951 go (\g) Send command to mysql server.
952 help (\h) Display this help.
953 nopager (\n) Disable pager, print to stdout.
954 notee (\t) Don't write into outfile.
955 pager (\P) Set PAGER [to_pager]. Print the query results via PAGER.
956 print (\p) Print current command.
957 prompt (\R) Change your mysql prompt.
958 quit (\q) Quit mysql.
959 rehash (\#) Rebuild completion hash.
960 source (\.) Execute an SQL script file. Takes a file name as an argument.
961 status (\s) Get status information from the server.
962 system (\!) Execute a system shell command.
963 tee (\T) Set outfile [to_outfile]. Append everything into given
964 outfile.
965 use (\u) Use another database. Takes database name as argument.
966 charset (\C) Switch to another charset. Might be needed for processing
967 binlog with multi-byte charsets.
968 warnings (\W) Show warnings after every statement.
969 nowarning (\w) Don't show warnings after every statement.
970 resetconnection(\x) Clean session context.
971 query_attributes Sets string parameters (name1 value1 name2 value2 ...)
972 for the next query to pick up.
973 ssl_session_data_print Serializes the current SSL session data to stdout
974 or file.
975 For server side help, type 'help contents'
976
977 If mysql is invoked with the --binary-mode option, all mysql commands
978 are disabled except charset and delimiter in noninteractive mode (for
979 input piped to mysql or loaded using the source command).
980
981 Each command has both a long and short form. The long form is not
982 case-sensitive; the short form is. The long form can be followed by an
983 optional semicolon terminator, but the short form should not.
984
985 The use of short-form commands within multiple-line /* ... */ comments
986 is not supported. Short-form commands do work within single-line /*!
987 ... */ version comments, as do /*+ ... */ optimizer-hint comments,
988 which are stored in object definitions. If there is a concern that
989 optimizer-hint comments may be stored in object definitions so that
990 dump files when reloaded with mysql would result in execution of such
991 commands, either invoke mysql with the --binary-mode option or use a
992 reload client other than mysql.
993
994 • help [arg], \h [arg], \? [arg], ? [arg]
995
996 Display a help message listing the available mysql commands.
997
998 If you provide an argument to the help command, mysql uses it as a
999 search string to access server-side help from the contents of the
1000 MySQL Reference Manual. For more information, see the section
1001 called “MYSQL CLIENT SERVER-SIDE HELP”.
1002
1003 • charset charset_name, \C charset_name
1004
1005 Change the default character set and issue a SET NAMES statement.
1006 This enables the character set to remain synchronized on the client
1007 and server if mysql is run with auto-reconnect enabled (which is
1008 not recommended), because the specified character set is used for
1009 reconnects.
1010
1011 • clear, \c
1012
1013 Clear the current input. Use this if you change your mind about
1014 executing the statement that you are entering.
1015
1016 • connect [db_name [host_name]], \r [db_name [host_name]]
1017
1018 Reconnect to the server. The optional database name and host name
1019 arguments may be given to specify the default database or the host
1020 where the server is running. If omitted, the current values are
1021 used.
1022
1023 If the connect command specifies a host name argument, that host
1024 takes precedence over any --dns-srv-name option given at mysql
1025 startup to specify a DNS SRV record.
1026
1027 • delimiter str, \d str
1028
1029 Change the string that mysql interprets as the separator between
1030 SQL statements. The default is the semicolon character (;).
1031
1032 The delimiter string can be specified as an unquoted or quoted
1033 argument on the delimiter command line. Quoting can be done with
1034 either single quote ('), double quote ("), or backtick (`)
1035 characters. To include a quote within a quoted string, either quote
1036 the string with a different quote character or escape the quote
1037 with a backslash (\) character. Backslash should be avoided outside
1038 of quoted strings because it is the escape character for MySQL. For
1039 an unquoted argument, the delimiter is read up to the first space
1040 or end of line. For a quoted argument, the delimiter is read up to
1041 the matching quote on the line.
1042
1043 mysql interprets instances of the delimiter string as a statement
1044 delimiter anywhere it occurs, except within quoted strings. Be
1045 careful about defining a delimiter that might occur within other
1046 words. For example, if you define the delimiter as X, it is not
1047 possible to use the word INDEX in statements. mysql interprets
1048 this as INDE followed by the delimiter X.
1049
1050 When the delimiter recognized by mysql is set to something other
1051 than the default of ;, instances of that character are sent to the
1052 server without interpretation. However, the server itself still
1053 interprets ; as a statement delimiter and processes statements
1054 accordingly. This behavior on the server side comes into play for
1055 multiple-statement execution (see Multiple Statement Execution
1056 Support[3]), and for parsing the body of stored procedures and
1057 functions, triggers, and events (see Section 25.1, “Defining Stored
1058 Programs”).
1059
1060 • edit, \e
1061
1062 Edit the current input statement. mysql checks the values of the
1063 EDITOR and VISUAL environment variables to determine which editor
1064 to use. The default editor is vi if neither variable is set.
1065
1066 The edit command works only in Unix.
1067
1068 • ego, \G
1069
1070 Send the current statement to the server to be executed and display
1071 the result using vertical format.
1072
1073 • exit, \q
1074
1075 Exit mysql.
1076
1077 • go, \g
1078
1079 Send the current statement to the server to be executed.
1080
1081 • nopager, \n
1082
1083 Disable output paging. See the description for pager.
1084
1085 The nopager command works only in Unix.
1086
1087 • notee, \t
1088
1089 Disable output copying to the tee file. See the description for
1090 tee.
1091
1092 • nowarning, \w
1093
1094 Disable display of warnings after each statement.
1095
1096 • pager [command], \P [command]
1097
1098 Enable output paging. By using the --pager option when you invoke
1099 mysql, it is possible to browse or search query results in
1100 interactive mode with Unix programs such as less, more, or any
1101 other similar program. If you specify no value for the option,
1102 mysql checks the value of the PAGER environment variable and sets
1103 the pager to that. Pager functionality works only in interactive
1104 mode.
1105
1106 Output paging can be enabled interactively with the pager command
1107 and disabled with nopager. The command takes an optional argument;
1108 if given, the paging program is set to that. With no argument, the
1109 pager is set to the pager that was set on the command line, or
1110 stdout if no pager was specified.
1111
1112 Output paging works only in Unix because it uses the popen()
1113 function, which does not exist on Windows. For Windows, the tee
1114 option can be used instead to save query output, although it is not
1115 as convenient as pager for browsing output in some situations.
1116
1117 • print, \p
1118
1119 Print the current input statement without executing it.
1120
1121 • prompt [str], \R [str]
1122
1123 Reconfigure the mysql prompt to the given string. The special
1124 character sequences that can be used in the prompt are described
1125 later in this section.
1126
1127 If you specify the prompt command with no argument, mysql resets
1128 the prompt to the default of mysql>.
1129
1130 • query_attributes name value [name value ...]
1131
1132 Define query attributes that apply to the next query sent to the
1133 server. For discussion of the purpose and use of query attributes,
1134 see Section 9.6, “Query Attributes”.
1135
1136 The query_attributes command follows these rules:
1137
1138 • The format and quoting rules for attribute names and values are
1139 the same as for the delimiter command.
1140
1141 • The command permits up to 32 attribute name/value pairs. Names
1142 and values may be up to 1024 characters long. If a name is
1143 given without a value, an error occurs.
1144
1145 • If multiple query_attributes commands are issued prior to query
1146 execution, only the last command applies. After sending the
1147 query, mysql clears the attribute set.
1148
1149 • If multiple attributes are defined with the same name, attempts
1150 to retrieve the attribute value have an undefined result.
1151
1152 • An attribute defined with an empty name cannot be retrieved by
1153 name.
1154
1155 • If a reconnect occurs while mysql executes the query, mysql
1156 restores the attributes after reconnecting so the query can be
1157 executed again with the same attributes.
1158
1159
1160 • quit, \q
1161
1162 Exit mysql.
1163
1164 • rehash, \#
1165
1166 Rebuild the completion hash that enables database, table, and
1167 column name completion while you are entering statements. (See the
1168 description for the --auto-rehash option.)
1169
1170 • resetconnection, \x
1171
1172 Reset the connection to clear the session state. This includes
1173 clearing any current query attributes defined using the
1174 query_attributes command.
1175
1176 Resetting a connection has effects similar to mysql_change_user()
1177 or an auto-reconnect except that the connection is not closed and
1178 reopened, and re-authentication is not done. See
1179 mysql_change_user()[4], and Automatic Reconnection Control[5].
1180
1181 This example shows how resetconnection clears a value maintained in
1182 the session state:
1183
1184 mysql> SELECT LAST_INSERT_ID(3);
1185 +-------------------+
1186 | LAST_INSERT_ID(3) |
1187 +-------------------+
1188 | 3 |
1189 +-------------------+
1190 mysql> SELECT LAST_INSERT_ID();
1191 +------------------+
1192 | LAST_INSERT_ID() |
1193 +------------------+
1194 | 3 |
1195 +------------------+
1196 mysql> resetconnection;
1197 mysql> SELECT LAST_INSERT_ID();
1198 +------------------+
1199 | LAST_INSERT_ID() |
1200 +------------------+
1201 | 0 |
1202 +------------------+
1203
1204 • source file_name, \. file_name
1205
1206 Read the named file and executes the statements contained therein.
1207 On Windows, specify path name separators as / or \\.
1208
1209 Quote characters are taken as part of the file name itself. For
1210 best results, the name should not include space characters.
1211
1212 • ssl_session_data_print [file_name]
1213
1214 Fetches, serializes, and optionally stores the session data of a
1215 successful connection. The optional file name and arguments may be
1216 given to specify the file to store serialized session data. If
1217 omitted, the session data is printed to stdout.
1218
1219 If the MySQL session is configured for reuse, session data from the
1220 file is deserialized and supplied to the connect command to
1221 reconnect. When the session is reused successfully, the status
1222 command contains a row showing SSL session reused: true while the
1223 client remains reconnected to the server.
1224
1225 • status, \s
1226
1227 Provide status information about the connection and the server you
1228 are using. If you are running with --safe-updates enabled, status
1229 also prints the values for the mysql variables that affect your
1230 queries.
1231
1232 • system command, \! command
1233
1234 Execute the given command using your default command interpreter.
1235
1236 Prior to MySQL 8.0.19, the system command works only in Unix. As of
1237 8.0.19, it also works on Windows.
1238
1239 • tee [file_name], \T [file_name]
1240
1241 By using the --tee option when you invoke mysql, you can log
1242 statements and their output. All the data displayed on the screen
1243 is appended into a given file. This can be very useful for
1244 debugging purposes also. mysql flushes results to the file after
1245 each statement, just before it prints its next prompt. Tee
1246 functionality works only in interactive mode.
1247
1248 You can enable this feature interactively with the tee command.
1249 Without a parameter, the previous file is used. The tee file can be
1250 disabled with the notee command. Executing tee again re-enables
1251 logging.
1252
1253 • use db_name, \u db_name
1254
1255 Use db_name as the default database.
1256
1257 • warnings, \W
1258
1259 Enable display of warnings after each statement (if there are any).
1260
1261 Here are a few tips about the pager command:
1262
1263 • You can use it to write to a file and the results go only to the
1264 file:
1265
1266 mysql> pager cat > /tmp/log.txt
1267
1268 You can also pass any options for the program that you want to use
1269 as your pager:
1270
1271 mysql> pager less -n -i -S
1272
1273 • In the preceding example, note the -S option. You may find it very
1274 useful for browsing wide query results. Sometimes a very wide
1275 result set is difficult to read on the screen. The -S option to
1276 less can make the result set much more readable because you can
1277 scroll it horizontally using the left-arrow and right-arrow keys.
1278 You can also use -S interactively within less to switch the
1279 horizontal-browse mode on and off. For more information, read the
1280 less manual page:
1281
1282 man less
1283
1284 • The -F and -X options may be used with less to cause it to exit if
1285 output fits on one screen, which is convenient when no scrolling is
1286 necessary:
1287
1288 mysql> pager less -n -i -S -F -X
1289
1290 • You can specify very complex pager commands for handling query
1291 output:
1292
1293 mysql> pager cat | tee /dr1/tmp/res.txt \
1294 | tee /dr2/tmp/res2.txt | less -n -i -S
1295
1296 In this example, the command would send query results to two files
1297 in two different directories on two different file systems mounted
1298 on /dr1 and /dr2, yet still display the results onscreen using
1299 less.
1300
1301 You can also combine the tee and pager functions. Have a tee file
1302 enabled and pager set to less, and you are able to browse the results
1303 using the less program and still have everything appended into a file
1304 the same time. The difference between the Unix tee used with the pager
1305 command and the mysql built-in tee command is that the built-in tee
1306 works even if you do not have the Unix tee available. The built-in tee
1307 also logs everything that is printed on the screen, whereas the Unix
1308 tee used with pager does not log quite that much. Additionally, tee
1309 file logging can be turned on and off interactively from within mysql.
1310 This is useful when you want to log some queries to a file, but not
1311 others.
1312
1313 The prompt command reconfigures the default mysql> prompt. The string
1314 for defining the prompt can contain the following special sequences.
1315
1316.br
1317.br
1318.br
131972
1320 ┌───────────────────────────┬────────────────────────────┐
1321 │Option │ Description │
1322 ├───────────────────────────┼────────────────────────────┤
1323 │ │ The current connection │
1324 │ │ identifier │
1325 ├───────────────────────────┼────────────────────────────┤
1326 │ │ A counter that increments │
1327 │ │ for each statement you │
1328 │ │ issue │
1329 ├───────────────────────────┼────────────────────────────┤
1330 │ │ The full current date │
1331 ├───────────────────────────┼────────────────────────────┤
1332 │ │ The default database │
1333 ├───────────────────────────┼────────────────────────────┤
1334 │ │ The server host │
1335 ├───────────────────────────┼────────────────────────────┤
1336 │ │ The current delimiter │
1337 ├───────────────────────────┼────────────────────────────┤
1338 │ │ Minutes of the current │
1339 │ │ time │
1340 ├───────────────────────────┼────────────────────────────┤
1341 │ │ A newline character │
1342 ├───────────────────────────┼────────────────────────────┤
1343 │ │ The current month in │
1344 │ │ three-letter format (Jan, │
1345 │ │ Feb, ...) │
1346 ├───────────────────────────┼────────────────────────────┤
1347 │ │ The current month in │
1348 │ │ numeric format │
1349 ├───────────────────────────┼────────────────────────────┤
1350 │P │ am/pm │
1351 ├───────────────────────────┼────────────────────────────┤
1352 │ │ The current TCP/IP port or │
1353 │ │ socket file │
1354 ├───────────────────────────┼────────────────────────────┤
1355 │ │ The current time, in │
1356 │ │ 24-hour military time │
1357 │ │ (0–23) │
1358 ├───────────────────────────┼────────────────────────────┤
1359 │ │ The current time, standard │
1360 │ │ 12-hour time (1–12) │
1361 ├───────────────────────────┼────────────────────────────┤
1362 │ │ Semicolon │
1363 ├───────────────────────────┼────────────────────────────┤
1364 │ │ Seconds of the current │
1365 │ │ time │
1366 ├───────────────────────────┼────────────────────────────┤
1367 │T │ Print an asterisk (*) if │
1368 │ │ the current session is │
1369 │ │ inside a │
1370 │ │ transaction block (from │
1371 │ │ MySQL 8.0.28) │
1372 ├───────────────────────────┼────────────────────────────┤
1373 │ │ A tab character │
1374 ├───────────────────────────┼────────────────────────────┤
1375 │U │ │
1376 │ │ Your full │
1377 │ │ user_name@host_name │
1378 │ │ account name │
1379 ├───────────────────────────┼────────────────────────────┤
1380 │ │ Your user name │
1381 ├───────────────────────────┼────────────────────────────┤
1382 │ │ The server version │
1383 ├───────────────────────────┼────────────────────────────┤
1384 │ │ The current day of the │
1385 │ │ week in three-letter │
1386 │ │ format (Mon, Tue, ...) │
1387 ├───────────────────────────┼────────────────────────────┤
1388 │ │ The current year, four │
1389 │ │ digits │
1390 ├───────────────────────────┼────────────────────────────┤
1391 │y │ The current year, two │
1392 │ │ digits │
1393 ├───────────────────────────┼────────────────────────────┤
1394 │_ │ A space │
1395 ├───────────────────────────┼────────────────────────────┤
1396 │\ │ A space (a space follows │
1397 │ │ the backslash) │
1398 ├───────────────────────────┼────────────────────────────┤
1399 │´ │ Single quote │
1400 ├───────────────────────────┼────────────────────────────┤
1401 │ │ Double quote │
1402 ├───────────────────────────┼────────────────────────────┤
1403 │T}:T{ A literal backslash │ │
1404 │character │ │
1405 ├───────────────────────────┼────────────────────────────┤
1406 │\fIx │ │
1407 │ │ x, for any “x” not │
1408 │ │ listed above │
1409 └───────────────────────────┴────────────────────────────┘
1410
1411 You can set the prompt in several ways:
1412
1413 • Use an environment variable. You can set the MYSQL_PS1 environment
1414 variable to a prompt string. For example:
1415
1416 export MYSQL_PS1="(\u@\h) [\d]> "
1417
1418 • Use a command-line option. You can set the --prompt option on the
1419 command line to mysql. For example:
1420
1421 $> mysql --prompt="(\u@\h) [\d]> "
1422 (user@host) [database]>
1423
1424 • Use an option file. You can set the prompt option in the [mysql]
1425 group of any MySQL option file, such as /etc/my.cnf or the .my.cnf
1426 file in your home directory. For example:
1427
1428 [mysql]
1429 prompt=(\\u@\\h) [\\d]>\\_
1430
1431 In this example, note that the backslashes are doubled. If you set
1432 the prompt using the prompt option in an option file, it is
1433 advisable to double the backslashes when using the special prompt
1434 options. There is some overlap in the set of permissible prompt
1435 options and the set of special escape sequences that are recognized
1436 in option files. (The rules for escape sequences in option files
1437 are listed in Section 4.2.2.2, “Using Option Files”.) The overlap
1438 may cause you problems if you use single backslashes. For example,
1439 \s is interpreted as a space rather than as the current seconds
1440 value. The following example shows how to define a prompt within an
1441 option file to include the current time in hh:mm:ss> format:
1442
1443 [mysql]
1444 prompt="\\r:\\m:\\s> "
1445
1446 • Set the prompt interactively. You can change your prompt
1447 interactively by using the prompt (or \R) command. For example:
1448
1449 mysql> prompt (\u@\h) [\d]>\_
1450 PROMPT set to '(\u@\h) [\d]>\_'
1451 (user@host) [database]>
1452 (user@host) [database]> prompt
1453 Returning to default PROMPT of mysql>
1454 mysql>
1455
1457 The mysql client can do these types of logging for statements executed
1458 interactively:
1459
1460 • On Unix, mysql writes the statements to a history file. By default,
1461 this file is named .mysql_history in your home directory. To
1462 specify a different file, set the value of the MYSQL_HISTFILE
1463 environment variable.
1464
1465 • On all platforms, if the --syslog option is given, mysql writes the
1466 statements to the system logging facility. On Unix, this is syslog;
1467 on Windows, it is the Windows Event Log. The destination where
1468 logged messages appear is system dependent. On Linux, the
1469 destination is often the /var/log/messages file.
1470
1471 The following discussion describes characteristics that apply to all
1472 logging types and provides information specific to each logging type.
1473
1474 • How Logging Occurs
1475
1476 • Controlling the History File
1477
1478 • syslog Logging Characteristics
1479 How Logging Occurs
1480
1481 For each enabled logging destination, statement logging occurs as
1482 follows:
1483
1484 • Statements are logged only when executed interactively. Statements
1485 are noninteractive, for example, when read from a file or a pipe.
1486 It is also possible to suppress statement logging by using the
1487 --batch or --execute option.
1488
1489 • Statements are ignored and not logged if they match any pattern in
1490 the “ignore” list. This list is described later.
1491
1492 • mysql logs each nonignored, nonempty statement line individually.
1493
1494 • If a nonignored statement spans multiple lines (not including the
1495 terminating delimiter), mysql concatenates the lines to form the
1496 complete statement, maps newlines to spaces, and logs the result,
1497 plus a delimiter.
1498
1499 Consequently, an input statement that spans multiple lines can be
1500 logged twice. Consider this input:
1501
1502 mysql> SELECT
1503 -> 'Today is'
1504 -> ,
1505 -> CURDATE()
1506 -> ;
1507
1508 In this case, mysql logs the “SELECT”, “'Today is'”, “,”, “CURDATE()”,
1509 and “;” lines as it reads them. It also logs the complete statement,
1510 after mapping SELECT\n'Today is'\n,\nCURDATE() to SELECT 'Today is' ,
1511 CURDATE(), plus a delimiter. Thus, these lines appear in logged output:
1512
1513 SELECT
1514 'Today is'
1515 ,
1516 CURDATE()
1517 ;
1518 SELECT 'Today is' , CURDATE();
1519
1520 mysql ignores for logging purposes statements that match any pattern in
1521 the “ignore” list. By default, the pattern list is
1522 "*IDENTIFIED*:*PASSWORD*", to ignore statements that refer to
1523 passwords. Pattern matching is not case-sensitive. Within patterns, two
1524 characters are special:
1525
1526 • ? matches any single character.
1527
1528 • * matches any sequence of zero or more characters.
1529
1530 To specify additional patterns, use the --histignore option or set the
1531 MYSQL_HISTIGNORE environment variable. (If both are specified, the
1532 option value takes precedence.) The value should be a list of one or
1533 more colon-separated patterns, which are appended to the default
1534 pattern list.
1535
1536 Patterns specified on the command line might need to be quoted or
1537 escaped to prevent your command interpreter from treating them
1538 specially. For example, to suppress logging for UPDATE and DELETE
1539 statements in addition to statements that refer to passwords, invoke
1540 mysql like this:
1541
1542 mysql --histignore="*UPDATE*:*DELETE*"
1543
1544 Controlling the History File
1545
1546 The .mysql_history file should be protected with a restrictive access
1547 mode because sensitive information might be written to it, such as the
1548 text of SQL statements that contain passwords. See Section 6.1.2.1,
1549 “End-User Guidelines for Password Security”. Statements in the file are
1550 accessible from the mysql client when the up-arrow key is used to
1551 recall the history. See Disabling Interactive History.
1552
1553 If you do not want to maintain a history file, first remove
1554 .mysql_history if it exists. Then use either of the following
1555 techniques to prevent it from being created again:
1556
1557 • Set the MYSQL_HISTFILE environment variable to /dev/null. To cause
1558 this setting to take effect each time you log in, put it in one of
1559 your shell's startup files.
1560
1561 • Create .mysql_history as a symbolic link to /dev/null; this need be
1562 done only once:
1563
1564 ln -s /dev/null $HOME/.mysql_history
1565 syslog Logging Characteristics
1566
1567 If the --syslog option is given, mysql writes interactive statements to
1568 the system logging facility. Message logging has the following
1569 characteristics.
1570
1571 Logging occurs at the “information” level. This corresponds to the
1572 LOG_INFO priority for syslog on Unix/Linux syslog capability and to
1573 EVENTLOG_INFORMATION_TYPE for the Windows Event Log. Consult your
1574 system documentation for configuration of your logging capability.
1575
1576 Message size is limited to 1024 bytes.
1577
1578 Messages consist of the identifier MysqlClient followed by these
1579 values:
1580
1581 • SYSTEM_USER
1582
1583 The operating system user name (login name) or -- if the user is
1584 unknown.
1585
1586 • MYSQL_USER
1587
1588 The MySQL user name (specified with the --user option) or -- if the
1589 user is unknown.
1590
1591 • CONNECTION_ID:
1592
1593 The client connection identifier. This is the same as the
1594 CONNECTION_ID() function value within the session.
1595
1596 • DB_SERVER
1597
1598 The server host or -- if the host is unknown.
1599
1600 • DB
1601
1602 The default database or -- if no database has been selected.
1603
1604 • QUERY
1605
1606 The text of the logged statement.
1607
1608 Here is a sample of output generated on Linux by using --syslog. This
1609 output is formatted for readability; each logged message actually takes
1610 a single line.
1611
1612 Mar 7 12:39:25 myhost MysqlClient[20824]:
1613 SYSTEM_USER:'oscar', MYSQL_USER:'my_oscar', CONNECTION_ID:23,
1614 DB_SERVER:'127.0.0.1', DB:'--', QUERY:'USE test;'
1615 Mar 7 12:39:28 myhost MysqlClient[20824]:
1616 SYSTEM_USER:'oscar', MYSQL_USER:'my_oscar', CONNECTION_ID:23,
1617 DB_SERVER:'127.0.0.1', DB:'test', QUERY:'SHOW TABLES;'
1618
1620 mysql> help search_string
1621
1622 If you provide an argument to the help command, mysql uses it as a
1623 search string to access server-side help from the contents of the MySQL
1624 Reference Manual. The proper operation of this command requires that
1625 the help tables in the mysql database be initialized with help topic
1626 information (see Section 5.1.17, “Server-Side Help Support”).
1627
1628 If there is no match for the search string, the search fails:
1629
1630 mysql> help me
1631 Nothing found
1632 Please try to run 'help contents' for a list of all accessible topics
1633
1634 Use help contents to see a list of the help categories:
1635
1636 mysql> help contents
1637 You asked for help about help category: "Contents"
1638 For more information, type 'help <item>', where <item> is one of the
1639 following categories:
1640 Account Management
1641 Administration
1642 Data Definition
1643 Data Manipulation
1644 Data Types
1645 Functions
1646 Functions and Modifiers for Use with GROUP BY
1647 Geographic Features
1648 Language Structure
1649 Plugins
1650 Storage Engines
1651 Stored Routines
1652 Table Maintenance
1653 Transactions
1654 Triggers
1655
1656 If the search string matches multiple items, mysql shows a list of
1657 matching topics:
1658
1659 mysql> help logs
1660 Many help items for your request exist.
1661 To make a more specific request, please type 'help <item>',
1662 where <item> is one of the following topics:
1663 SHOW
1664 SHOW BINARY LOGS
1665 SHOW ENGINE
1666 SHOW LOGS
1667
1668 Use a topic as the search string to see the help entry for that topic:
1669
1670 mysql> help show binary logs
1671 Name: 'SHOW BINARY LOGS'
1672 Description:
1673 Syntax:
1674 SHOW BINARY LOGS
1675 SHOW MASTER LOGS
1676 Lists the binary log files on the server. This statement is used as
1677 part of the procedure described in [purge-binary-logs], that shows how
1678 to determine which logs can be purged.
1679
1680 mysql> SHOW BINARY LOGS;
1681 +---------------+-----------+-----------+
1682 | Log_name | File_size | Encrypted |
1683 +---------------+-----------+-----------+
1684 | binlog.000015 | 724935 | Yes |
1685 | binlog.000016 | 733481 | Yes |
1686 +---------------+-----------+-----------+
1687
1688 The search string can contain the wildcard characters % and _. These
1689 have the same meaning as for pattern-matching operations performed with
1690 the LIKE operator. For example, HELP rep% returns a list of topics that
1691 begin with rep:
1692
1693 mysql> HELP rep%
1694 Many help items for your request exist.
1695 To make a more specific request, please type 'help <item>',
1696 where <item> is one of the following
1697 topics:
1698 REPAIR TABLE
1699 REPEAT FUNCTION
1700 REPEAT LOOP
1701 REPLACE
1702 REPLACE FUNCTION
1703
1705 The mysql client typically is used interactively, like this:
1706
1707 mysql db_name
1708
1709 However, it is also possible to put your SQL statements in a file and
1710 then tell mysql to read its input from that file. To do so, create a
1711 text file text_file that contains the statements you wish to execute.
1712 Then invoke mysql as shown here:
1713
1714 mysql db_name < text_file
1715
1716 If you place a USE db_name statement as the first statement in the
1717 file, it is unnecessary to specify the database name on the command
1718 line:
1719
1720 mysql < text_file
1721
1722 If you are already running mysql, you can execute an SQL script file
1723 using the source command or \. command:
1724
1725 mysql> source file_name
1726 mysql> \. file_name
1727
1728 Sometimes you may want your script to display progress information to
1729 the user. For this you can insert statements like this:
1730
1731 SELECT '<info_to_display>' AS ' ';
1732
1733 The statement shown outputs <info_to_display>.
1734
1735 You can also invoke mysql with the --verbose option, which causes each
1736 statement to be displayed before the result that it produces.
1737
1738 mysql ignores Unicode byte order mark (BOM) characters at the beginning
1739 of input files. Previously, it read them and sent them to the server,
1740 resulting in a syntax error. Presence of a BOM does not cause mysql to
1741 change its default character set. To do that, invoke mysql with an
1742 option such as --default-character-set=utf8mb4.
1743
1744 For more information about batch mode, see Section 3.5, “Using mysql in
1745 Batch Mode”.
1746
1748 This section provides information about techniques for more effective
1749 use of mysql and about mysql operational behavior.
1750
1751 • Input-Line Editing
1752
1753 • Disabling Interactive History
1754
1755 • Unicode Support on Windows
1756
1757 • Displaying Query Results Vertically
1758
1759 • Using Safe-Updates Mode (--safe-updates)
1760
1761 • Disabling mysql Auto-Reconnect
1762
1763 • mysql Client Parser Versus Server Parser
1764 Input-Line Editing
1765
1766 mysql supports input-line editing, which enables you to modify the
1767 current input line in place or recall previous input lines. For
1768 example, the left-arrow and right-arrow keys move horizontally within
1769 the current input line, and the up-arrow and down-arrow keys move up
1770 and down through the set of previously entered lines. Backspace
1771 deletes the character before the cursor and typing new characters
1772 enters them at the cursor position. To enter the line, press Enter.
1773
1774 On Windows, the editing key sequences are the same as supported for
1775 command editing in console windows. On Unix, the key sequences depend
1776 on the input library used to build mysql (for example, the libedit or
1777 readline library).
1778
1779 Documentation for the libedit and readline libraries is available
1780 online. To change the set of key sequences permitted by a given input
1781 library, define key bindings in the library startup file. This is a
1782 file in your home directory: .editrc for libedit and .inputrc for
1783 readline.
1784
1785 For example, in libedit, Control+W deletes everything before the
1786 current cursor position and Control+U deletes the entire line. In
1787 readline, Control+W deletes the word before the cursor and Control+U
1788 deletes everything before the current cursor position. If mysql was
1789 built using libedit, a user who prefers the readline behavior for these
1790 two keys can put the following lines in the .editrc file (creating the
1791 file if necessary):
1792
1793 bind "^W" ed-delete-prev-word
1794 bind "^U" vi-kill-line-prev
1795
1796 To see the current set of key bindings, temporarily put a line that
1797 says only bind at the end of .editrc. mysql shows the bindings when it
1798 starts. Disabling Interactive History
1799
1800 The up-arrow key enables you to recall input lines from current and
1801 previous sessions. In cases where a console is shared, this behavior
1802 may be unsuitable. mysql supports disabling the interactive history
1803 partially or fully, depending on the host platform.
1804
1805 On Windows, the history is stored in memory. Alt+F7 deletes all input
1806 lines stored in memory for the current history buffer. It also deletes
1807 the list of sequential numbers in front of the input lines displayed
1808 with F7 and recalled (by number) with F9. New input lines entered after
1809 you press Alt+F7 repopulate the current history buffer. Clearing the
1810 buffer does not prevent logging to the Windows Event Viewer, if the
1811 --syslog option was used to start mysql. Closing the console window
1812 also clears the current history buffer.
1813
1814 To disable interactive history on Unix, first delete the .mysql_history
1815 file, if it exists (previous entries are recalled otherwise). Then
1816 start mysql with the --histignore="*" option to ignore all new input
1817 lines. To re-enable the recall (and logging) behavior, restart mysql
1818 without the option.
1819
1820 If you prevent the .mysql_history file from being created (see
1821 Controlling the History File) and use --histignore="*" to start the
1822 mysql client, the interactive history recall facility is disabled
1823 fully. Alternatively, if you omit the --histignore option, you can
1824 recall the input lines entered during the current session. Unicode
1825 Support on Windows
1826
1827 Windows provides APIs based on UTF-16LE for reading from and writing to
1828 the console; the mysql client for Windows is able to use these APIs.
1829 The Windows installer creates an item in the MySQL menu named MySQL
1830 command line client - Unicode. This item invokes the mysql client with
1831 properties set to communicate through the console to the MySQL server
1832 using Unicode.
1833
1834 To take advantage of this support manually, run mysql within a console
1835 that uses a compatible Unicode font and set the default character set
1836 to a Unicode character set that is supported for communication with the
1837 server:
1838
1839 1. Open a console window.
1840
1841 2. Go to the console window properties, select the font tab, and
1842 choose Lucida Console or some other compatible Unicode font. This
1843 is necessary because console windows start by default using a DOS
1844 raster font that is inadequate for Unicode.
1845
1846 3. Execute mysql.exe with the --default-character-set=utf8mb4 (or
1847 utf8mb3) option. This option is necessary because utf16le is one of
1848 the character sets that cannot be used as the client character set.
1849 See the section called “Impermissible Client Character Sets”.
1850
1851 With those changes, mysql uses the Windows APIs to communicate with the
1852 console using UTF-16LE, and communicate with the server using UTF-8.
1853 (The menu item mentioned previously sets the font and character set as
1854 just described.)
1855
1856 To avoid those steps each time you run mysql, you can create a shortcut
1857 that invokes mysql.exe. The shortcut should set the console font to
1858 Lucida Console or some other compatible Unicode font, and pass the
1859 --default-character-set=utf8mb4 (or utf8mb3) option to mysql.exe.
1860
1861 Alternatively, create a shortcut that only sets the console font, and
1862 set the character set in the [mysql] group of your my.ini file:
1863
1864 [mysql]
1865 default-character-set=utf8mb4 # or utf8mb3
1866
1867 Displaying Query Results Vertically
1868
1869 Some query results are much more readable when displayed vertically,
1870 instead of in the usual horizontal table format. Queries can be
1871 displayed vertically by terminating the query with \G instead of a
1872 semicolon. For example, longer text values that include newlines often
1873 are much easier to read with vertical output:
1874
1875 mysql> SELECT * FROM mails WHERE LENGTH(txt) < 300 LIMIT 300,1\G
1876 *************************** 1. row ***************************
1877 msg_nro: 3068
1878 date: 2000-03-01 23:29:50
1879 time_zone: +0200
1880 mail_from: Jones
1881 reply: jones@example.com
1882 mail_to: "John Smith" <smith@example.com>
1883 sbj: UTF-8
1884 txt: >>>>> "John" == John Smith writes:
1885 John> Hi. I think this is a good idea. Is anyone familiar
1886 John> with UTF-8 or Unicode? Otherwise, I'll put this on my
1887 John> TODO list and see what happens.
1888 Yes, please do that.
1889 Regards,
1890 Jones
1891 file: inbox-jani-1
1892 hash: 190402944
1893 1 row in set (0.09 sec)
1894
1895 Using Safe-Updates Mode (--safe-updates)
1896
1897 For beginners, a useful startup option is --safe-updates (or
1898 --i-am-a-dummy, which has the same effect). Safe-updates mode is
1899 helpful for cases when you might have issued an UPDATE or DELETE
1900 statement but forgotten the WHERE clause indicating which rows to
1901 modify. Normally, such statements update or delete all rows in the
1902 table. With --safe-updates, you can modify rows only by specifying the
1903 key values that identify them, or a LIMIT clause, or both. This helps
1904 prevent accidents. Safe-updates mode also restricts SELECT statements
1905 that produce (or are estimated to produce) very large result sets.
1906
1907 The --safe-updates option causes mysql to execute the following
1908 statement when it connects to the MySQL server, to set the session
1909 values of the sql_safe_updates, sql_select_limit, and max_join_size
1910 system variables:
1911
1912 SET sql_safe_updates=1, sql_select_limit=1000, max_join_size=1000000;
1913
1914 The SET statement affects statement processing as follows:
1915
1916 • Enabling sql_safe_updates causes UPDATE and DELETE statements to
1917 produce an error if they do not specify a key constraint in the
1918 WHERE clause, or provide a LIMIT clause, or both. For example:
1919
1920 UPDATE tbl_name SET not_key_column=val WHERE key_column=val;
1921 UPDATE tbl_name SET not_key_column=val LIMIT 1;
1922
1923 • Setting sql_select_limit to 1,000 causes the server to limit all
1924 SELECT result sets to 1,000 rows unless the statement includes a
1925 LIMIT clause.
1926
1927 • Setting max_join_size to 1,000,000 causes multiple-table SELECT
1928 statements to produce an error if the server estimates it must
1929 examine more than 1,000,000 row combinations.
1930
1931 To specify result set limits different from 1,000 and 1,000,000, you
1932 can override the defaults by using the --select-limit and
1933 --max-join-size options when you invoke mysql:
1934
1935 mysql --safe-updates --select-limit=500 --max-join-size=10000
1936
1937 It is possible for UPDATE and DELETE statements to produce an error in
1938 safe-updates mode even with a key specified in the WHERE clause, if the
1939 optimizer decides not to use the index on the key column:
1940
1941 • Range access on the index cannot be used if memory usage exceeds
1942 that permitted by the range_optimizer_max_mem_size system variable.
1943 The optimizer then falls back to a table scan. See the section
1944 called “Limiting Memory Use for Range Optimization”.
1945
1946 • If key comparisons require type conversion, the index may not be
1947 used (see Section 8.3.1, “How MySQL Uses Indexes”). Suppose that an
1948 indexed string column c1 is compared to a numeric value using WHERE
1949 c1 = 2222. For such comparisons, the string value is converted to a
1950 number and the operands are compared numerically (see Section 12.3,
1951 “Type Conversion in Expression Evaluation”), preventing use of the
1952 index. If safe-updates mode is enabled, an error occurs.
1953
1954 As of MySQL 8.0.13, safe-updates mode also includes these behaviors:
1955
1956 • EXPLAIN with UPDATE and DELETE statements does not produce
1957 safe-updates errors. This enables use of EXPLAIN plus SHOW WARNINGS
1958 to see why an index is not used, which can be helpful in cases such
1959 as when a range_optimizer_max_mem_size violation or type conversion
1960 occurs and the optimizer does not use an index even though a key
1961 column was specified in the WHERE clause.
1962
1963 • When a safe-updates error occurs, the error message includes the
1964 first diagnostic that was produced, to provide information about
1965 the reason for failure. For example, the message may indicate that
1966 the range_optimizer_max_mem_size value was exceeded or type
1967 conversion occurred, either of which can preclude use of an index.
1968
1969 • For multiple-table deletes and updates, an error is produced with
1970 safe updates enabled only if any target table uses a table scan.
1971 Disabling mysql Auto-Reconnect
1972
1973 If the mysql client loses its connection to the server while sending a
1974 statement, it immediately and automatically tries to reconnect once to
1975 the server and send the statement again. However, even if mysql
1976 succeeds in reconnecting, your first connection has ended and all your
1977 previous session objects and settings are lost: temporary tables, the
1978 autocommit mode, and user-defined and session variables. Also, any
1979 current transaction rolls back. This behavior may be dangerous for you,
1980 as in the following example where the server was shut down and
1981 restarted between the first and second statements without you knowing
1982 it:
1983
1984 mysql> SET @a=1;
1985 Query OK, 0 rows affected (0.05 sec)
1986 mysql> INSERT INTO t VALUES(@a);
1987 ERROR 2006: MySQL server has gone away
1988 No connection. Trying to reconnect...
1989 Connection id: 1
1990 Current database: test
1991 Query OK, 1 row affected (1.30 sec)
1992 mysql> SELECT * FROM t;
1993 +------+
1994 | a |
1995 +------+
1996 | NULL |
1997 +------+
1998 1 row in set (0.05 sec)
1999
2000 The @a user variable has been lost with the connection, and after the
2001 reconnection it is undefined. If it is important to have mysql
2002 terminate with an error if the connection has been lost, you can start
2003 the mysql client with the --skip-reconnect option.
2004
2005 For more information about auto-reconnect and its effect on state
2006 information when a reconnection occurs, see Automatic Reconnection
2007 Control[5]. mysql Client Parser Versus Server Parser
2008
2009 The mysql client uses a parser on the client side that is not a
2010 duplicate of the complete parser used by the mysqld server on the
2011 server side. This can lead to differences in treatment of certain
2012 constructs. Examples:
2013
2014 • The server parser treats strings delimited by " characters as
2015 identifiers rather than as plain strings if the ANSI_QUOTES SQL
2016 mode is enabled.
2017
2018 The mysql client parser does not take the ANSI_QUOTES SQL mode into
2019 account. It treats strings delimited by ", ', and ` characters the
2020 same, regardless of whether ANSI_QUOTES is enabled.
2021
2022 • Within /*! ... */ and /*+ ... */ comments, the mysql client parser
2023 interprets short-form mysql commands. The server parser does not
2024 interpret them because these commands have no meaning on the server
2025 side.
2026
2027 If it is desirable for mysql not to interpret short-form commands
2028 within comments, a partial workaround is to use the --binary-mode
2029 option, which causes all mysql commands to be disabled except \C
2030 and \d in noninteractive mode (for input piped to mysql or loaded
2031 using the source command).
2032
2034 Copyright © 1997, 2023, Oracle and/or its affiliates.
2035
2036 This documentation is free software; you can redistribute it and/or
2037 modify it only under the terms of the GNU General Public License as
2038 published by the Free Software Foundation; version 2 of the License.
2039
2040 This documentation is distributed in the hope that it will be useful,
2041 but WITHOUT ANY WARRANTY; without even the implied warranty of
2042 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
2043 General Public License for more details.
2044
2045 You should have received a copy of the GNU General Public License along
2046 with the program; if not, write to the Free Software Foundation, Inc.,
2047 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA or see
2048 http://www.gnu.org/licenses/.
2049
2050
2052 1. MySQL Shell 8.0
2053 https://dev.mysql.com/doc/mysql-shell/8.0/en/
2054
2055 2. C API Basic Data Structures
2056 https://dev.mysql.com/doc/c-api/8.0/en/c-api-data-structures.html
2057
2058 3. Multiple Statement Execution Support
2059 https://dev.mysql.com/doc/c-api/8.0/en/c-api-multiple-queries.html
2060
2061 4. mysql_change_user()
2062 https://dev.mysql.com/doc/c-api/8.0/en/mysql-change-user.html
2063
2064 5. Automatic Reconnection Control
2065 https://dev.mysql.com/doc/c-api/8.0/en/c-api-auto-reconnect.html
2066
2068 For more information, please refer to the MySQL Reference Manual, which
2069 may already be installed locally and which is also available online at
2070 http://dev.mysql.com/doc/.
2071
2073 Oracle Corporation (http://dev.mysql.com/).
2074
2075
2076
2077MySQL 8.0 08/31/2023 MYSQL(1)