ROLLBACK — abort the current transaction
ROLLBACK [ WORK | TRANSACTION ] [ AND [ NO ] CHAIN ]
   ROLLBACK rolls back the current transaction and causes
   all the updates made by the transaction to be discarded.
  
WORKTRANSACTIONOptional key words. They have no effect.
AND CHAIN
      If AND CHAIN is specified, a new transaction is
      immediately started with the same transaction characteristics (see SET TRANSACTION) as the just finished one.  Otherwise,
      no new transaction is started.
     
Use COMMIT to successfully terminate a transaction.
   Issuing ROLLBACK outside of a transaction
   block emits a warning and otherwise has no effect.  ROLLBACK AND
   CHAIN outside of a transaction block is an error.
  
To abort all changes:
ROLLBACK;
   The command ROLLBACK conforms to the SQL standard.  The
   form ROLLBACK TRANSACTION is a PostgreSQL extension.