Abort the current transaction
ROLLBACK [ WORK | TRANSACTION ]
ROLLBACK rolls back the current transaction and causes all the updates made by the transaction to be discarded.
Optional key words. They have no effect.
Use COMMIT(7) to successfully terminate a transaction.
Issuing ROLLBACK outside of a transaction block emits a warning and otherwise has no effect.
To abort all changes:
The SQL standard only specifies the two forms ROLLBACK and ROLLBACK WORK. Otherwise, this command is fully conforming.