PostgreSQL, Second Edition

UPDATE

Now that you've seen a number of ways to view your data, let's see how to modify (and delete) existing data.

The UPDATE command modifies data in one or more rows. The general form of the UPDATE command is

UPDATE table SET column = expression [, ...] [WHERE condition]

Using the UPDATE command is straightforward: The WHERE clause (if present) determines which rows will be updated and the SET clause determines which columns will be updated (and the new values).

You might have noticed in earlier examples that one of the tapes had a duration of '4 days, 01:36'—that's obviously a mistake. You can correct this problem with the UPDATE command as follows:

 movies=# UPDATE tapes SET duration = '4 hours 36 minutes' movies-# WHERE tape_id = 'OW-42201'; ...