DROP EXTENSION — remove an extension
DROP EXTENSION [ IF EXISTS ] name [, ...] [ CASCADE | RESTRICT ]
   DROP EXTENSION removes extensions from the database.
   Dropping an extension causes its member objects, and other explicitly
   dependent routines (see ALTER ROUTINE,
   the depends on extension action), to be dropped as well.
  
   You must own the extension to use DROP EXTENSION.
  
IF EXISTSDo not throw an error if the extension does not exist. A notice is issued in this case.
nameThe name of an installed extension.
CASCADEAutomatically drop objects that depend on the extension, and in turn all objects that depend on those objects (see Section 5.14).
RESTRICTThis option prevents the specified extensions from being dropped if other objects, besides these extensions, their members, and their explicitly dependent routines, depend on them. This is the default.
   To remove the extension hstore from the current
   database:
DROP EXTENSION hstore;
   This command will fail if any of hstore's objects
   are in use in the database, for example if any tables have columns
   of the hstore type.  Add the CASCADE option to
   forcibly remove those dependent objects as well.
  
   DROP EXTENSION is a PostgreSQL
   extension.