The WHERE Clause

The WHERE clause specifies which rows are to be updated. For example, in the unlikely event that northern California is renamed Pacifica (abbreviated PC) and the people of Oakland vote to change the name of their city to Bay City, here is how to update the authors table for all former Oakland residents whose addresses are now out of date:

UPDATE authors
SET state = 'PC', city = 'Bay City'
WHERE state = 'CA' AND city = 'Oakland'