1DELETE(7) SQL Commands DELETE(7)
2
6 DELETE - delete rows of a table
7
10 DELETE FROM [ ONLY ] table [ * ] [ [ AS ] alias ]
11 [ USING usinglist ]
12 [ WHERE condition | WHERE CURRENT OF cursor_name ]
13 [ RETURNING * | output_expression [ [ AS ] output_name ] [, ...] ]
14
17 DELETE deletes rows that satisfy the WHERE clause from the specified
18 table. If the WHERE clause is absent, the effect is to delete all rows
19 in the table. The result is a valid, but empty table.
20 Tip: TRUNCATE [truncate(7)] is a PostgreSQL extension that pro‐
22 vides a faster mechanism to remove all rows from a table.
23 There are two ways to delete rows in a table using information con‐
26 tained in other tables in the database: using sub-selects, or specify‐
27 ing additional tables in the USING clause. Which technique is more
28 appropriate depends on the specific circumstances.
29 The optional RETURNING clause causes DELETE to compute and return
31 value(s) based on each row actually deleted. Any expression using the
32 table's columns, and/or columns of other tables mentioned in USING, can
33 be computed. The syntax of the RETURNING list is identical to that of
34 the output list of SELECT.
35 You must have the DELETE privilege on the table to delete from it, as
37 well as the SELECT privilege for any table in the USING clause or whose
38 values are read in the condition.
39
41 table The name (optionally schema-qualified) of the table to delete
42 rows from. If ONLY is specified before the table name, matching
43 rows are deleted from the named table only. If ONLY is not spec‐
44 ified, matching rows are also deleted from any tables inheriting
45 from the named table. Optionally, * can be specified after the
46 table name to explicitly indicate that descendant tables are
47 included.
48 alias A substitute name for the target table. When an alias is pro‐
50 vided, it completely hides the actual name of the table. For
51 example, given DELETE FROM foo AS f, the remainder of the DELETE
52 statement must refer to this table as f not foo.
53 usinglist
55 A list of table expressions, allowing columns from other tables
56 to appear in the WHERE condition. This is similar to the list of
57 tables that can be specified in the FROM Clause [select(7)] of a
58 SELECT statement; for example, an alias for the table name can
59 be specified. Do not repeat the target table in the usinglist,
60 unless you wish to set up a self-join.
61 condition
63 An expression that returns a value of type boolean. Only rows
64 for which this expression returns true will be deleted.
65 cursor_name
67 The name of the cursor to use in a WHERE CURRENT OF condition.
68 The row to be deleted is the one most recently fetched from this
69 cursor. The cursor must be a non-grouping query on the DELETE's
70 target table. Note that WHERE CURRENT OF cannot be specified
71 together with a Boolean condition. See DECLARE [declare(7)] for
72 more information about using cursors with WHERE CURRENT OF.
73 output_expression
75 An expression to be computed and returned by the DELETE command
76 after each row is deleted. The expression can use any column
77 names of the table or table(s) listed in USING. Write * to
78 return all columns.
79 output_name
81 A name to use for a returned column.
82
84 On successful completion, a DELETE command returns a command tag of the
85 form
86 DELETE count
88 The count is the number of rows deleted. If count is 0, no rows matched
90 the condition (this is not considered an error).
91 If the DELETE command contains a RETURNING clause, the result will be
93 similar to that of a SELECT statement containing the columns and values
94 defined in the RETURNING list, computed over the row(s) deleted by the
95 command.
96
98 PostgreSQL lets you reference columns of other tables in the WHERE con‐
99 dition by specifying the other tables in the USING clause. For example,
100 to delete all films produced by a given producer, one can do:
101 DELETE FROM films USING producers
103 WHERE producer_id = producers.id AND producers.name = 'foo';
104 What is essentially happening here is a join between films and produc‐
106 ers, with all successfully joined films rows being marked for deletion.
107 This syntax is not standard. A more standard way to do it is:
108 DELETE FROM films
110 WHERE producer_id IN (SELECT id FROM producers WHERE name = 'foo');
111 In some cases the join style is easier to write or faster to execute
113 than the sub-select style.
114
116 Delete all films but musicals:
117 DELETE FROM films WHERE kind <> 'Musical';
119 Clear the table films:
122 DELETE FROM films;
124 Delete completed tasks, returning full details of the deleted rows:
127 DELETE FROM tasks WHERE status = 'DONE' RETURNING *;
129 Delete the row of tasks on which the cursor c_tasks is currently posi‐
132 tioned:
133 DELETE FROM tasks WHERE CURRENT OF c_tasks;
135
138 This command conforms to the SQL standard, except that the USING and
139 RETURNING clauses are PostgreSQL extensions.
140SQL - Language Statements 2014-02-17 DELETE(7)