DROP COLLATION — 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.