ROLLBACK — 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 to successfully terminate a transaction.
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
WORK. Otherwise, this command is fully conforming.