ROLLBACK - abort the current transaction
ROLLBACK [ WORK | TRANSACTION ]
rolls back the current transaction and causes all the updates
made by the transaction to be discarded.
Optional key words. They have no effect.
(7) to successfully terminate a transaction.
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.
(7), ROLLBACK TO SAVEPOINT