1CREATE COLLATION(7) PostgreSQL 11.6 Documentation CREATE COLLATION(7)
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6 CREATE_COLLATION - define a new collation
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9 CREATE COLLATION [ IF NOT EXISTS ] name (
10 [ LOCALE = locale, ]
11 [ LC_COLLATE = lc_collate, ]
12 [ LC_CTYPE = lc_ctype, ]
13 [ PROVIDER = provider, ]
14 [ VERSION = version ]
15 )
16 CREATE COLLATION [ IF NOT EXISTS ] name FROM existing_collation
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19 CREATE COLLATION defines a new collation using the specified operating
20 system locale settings, or by copying an existing collation.
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22 To be able to create a collation, you must have CREATE privilege on the
23 destination schema.
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26 IF NOT EXISTS
27 Do not throw an error if a collation with the same name already
28 exists. A notice is issued in this case. Note that there is no
29 guarantee that the existing collation is anything like the one that
30 would have been created.
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32 name
33 The name of the collation. The collation name can be
34 schema-qualified. If it is not, the collation is defined in the
35 current schema. The collation name must be unique within that
36 schema. (The system catalogs can contain collations with the same
37 name for other encodings, but these are ignored if the database
38 encoding does not match.)
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40 locale
41 This is a shortcut for setting LC_COLLATE and LC_CTYPE at once. If
42 you specify this, you cannot specify either of those parameters.
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44 lc_collate
45 Use the specified operating system locale for the LC_COLLATE locale
46 category.
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48 lc_ctype
49 Use the specified operating system locale for the LC_CTYPE locale
50 category.
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52 provider
53 Specifies the provider to use for locale services associated with
54 this collation. Possible values are: icu, libc. libc is the
55 default. The available choices depend on the operating system and
56 build options.
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58 version
59 Specifies the version string to store with the collation. Normally,
60 this should be omitted, which will cause the version to be computed
61 from the actual version of the collation as provided by the
62 operating system. This option is intended to be used by pg_upgrade
63 for copying the version from an existing installation.
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65 See also ALTER COLLATION (ALTER_COLLATION(7)) for how to handle
66 collation version mismatches.
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68 existing_collation
69 The name of an existing collation to copy. The new collation will
70 have the same properties as the existing one, but it will be an
71 independent object.
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74 Use DROP COLLATION to remove user-defined collations.
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76 See Section 23.2.2.3 for more information on how to create collations.
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78 When using the libc collation provider, the locale must be applicable
79 to the current database encoding. See CREATE DATABASE
80 (CREATE_DATABASE(7)) for the precise rules.
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83 To create a collation from the operating system locale fr_FR.utf8
84 (assuming the current database encoding is UTF8):
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86 CREATE COLLATION french (locale = 'fr_FR.utf8');
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88 To create a collation using the ICU provider using German phone book
89 sort order:
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91 CREATE COLLATION german_phonebook (provider = icu, locale = 'de-u-co-phonebk');
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93 To create a collation from an existing collation:
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95 CREATE COLLATION german FROM "de_DE";
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97 This can be convenient to be able to use operating-system-independent
98 collation names in applications.
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101 There is a CREATE COLLATION statement in the SQL standard, but it is
102 limited to copying an existing collation. The syntax to create a new
103 collation is a PostgreSQL extension.
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106 ALTER COLLATION (ALTER_COLLATION(7)), DROP COLLATION
107 (DROP_COLLATION(7))
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111PostgreSQL 11.6 2019 CREATE COLLATION(7)