Remove a collation
DROP COLLATION [ IF EXISTS ] name [ CASCADE | RESTRICT ]
DROP COLLATION removes a previously defined collation. To be able to drop a collation, you must own the collation.
IF EXISTS
Do not throw an error if the collation does not exist. A notice is issued in this case.
name
The name of the collation. The collation name can be schema-qualified.
CASCADE
Automatically drop objects that depend on the collation.
RESTRICT
Refuse to drop the collation if any objects depend on it. This is the default.
To drop the collation named german:
DROP COLLATION german;
The DROP COLLATION command conforms to the SQL standard, apart from the IF EXISTS option, which is a PostgreSQL extension.
ALTER COLLATION (ALTER_COLLATION(7)), CREATE COLLATION (CREATE_COLLATION(7))