pg_collation

The catalog pg_collation describes the available collations, which are essentially mappings from an SQL name to operating system locale categories.

Reading PG 18current·documented in 17 of 24 versions, 9.1 to 20

Columns 12

As listed in the PostgreSQL 18 manual.

Column	Type	Description / reference
`oid`	`oid`NOT NULL	Row identifier
`collname`	`name`NOT NULL	Collation name (unique per namespace and encoding)
`collnamespace`	`oid`NOT NULL	The OID of the namespace that contains this collation pg_namespace.oid
`collowner`	`oid`NOT NULL	Owner of the collation pg_authid.oid
`collprovider`	`char`NOT NULL	Provider of the collation: d = database default, b = builtin, c = libc, i = icu
`collisdeterministic`	`bool`NOT NULL	Is the collation deterministic?
`collencoding`	`int4`NOT NULL	Encoding in which the collation is applicable, or -1 if it works for any encoding
`collcollate`	`text`	LC_COLLATE for this collation object. If the provider is not libc, collcollate is NULL and colllocale is used instead.
`collctype`	`text`	LC_CTYPE for this collation object. If the provider is not libc, collctype is NULL and colllocale is used instead.
`colllocale`	`text`	Collation provider locale name for this collation object. If the provider is libc, colllocale is NULL; collcollate and collctype are used instead.
`collicurules`	`text`	ICU collation rules for this collation object
`collversion`	`text`	Provider-specific version of the collation. This is recorded when the collation is created and then checked when it is used, to detect changes in the collation definition that could lead to data corruption.