DROP USER MAPPING — remove a user mapping for a foreign server
DROP USER MAPPING [ IF EXISTS ] FOR { user_name | USER | CURRENT_USER | PUBLIC } SERVER server_name
DROP USER MAPPING removes an existing user mapping from foreign server.
The owner of a foreign server can drop user mappings for that server for any user. Also, a user can drop a user mapping for their own user name if USAGE privilege on the server has been granted to the user.
IF EXISTSDo not throw an error if the user mapping does not exist. A notice is issued in this case.
user_nameUser name of the mapping. CURRENT_USER and USER match the name of the current user. PUBLIC is used to match all present and future user names in the system.
server_nameServer name of the user mapping.
Drop a user mapping bob, server foo if it exists:
DROP USER MAPPING IF EXISTS FOR bob SERVER foo;
DROP USER MAPPING conforms to ISO/IEC 9075-9 (SQL/MED). The IF EXISTS clause is a PostgreSQL extension.
Read the upstream documentation. For corrections, first check the current version.