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.
Do not throw an error if the collation does not exist. A notice is issued in this case.
The name of the collation. The collation name can be schema-qualified.
Automatically drop objects that depend on the collation.
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.