ROLLBACK -- Aborts the current transaction block and abandons any modifications it would have made.
ROLLBACK [ WORK | TRANSACTION ]
WORK | TRANSACTION
A pair of optional noise keywords. They can be ignored, or used to make your SQL more readable.
The message returned when a transaction is aborted successfully.
NOTICE: ROLLBACK: no transaction in progress
The notice returned if there is not a transaction in progress to rollback.
Use ROLLBACK to abort a transaction in progress and discard all changes either already made or queued to be made on COMMIT.
The following example demonstrates how to rollback an accidental delete performed within a transaction block:
DELETE FROM shipments;