If the WHERE clause in an UPDATE matches multiple rows, the SET clause will be applied to all matched rows. This rule allows you to update values on multiple rows in a single UPDATE statement. Here is a good example:

UPDATE ggl_links SET counts = 9, notes = 'Wrong URL'

WHERE id >= 250;

3 rows updated.

SELECT * FROM ggl_links WHERE id >= 250;

 ID URL   NOTES  COUNTS CREATED

----- -------------------- ------------ ------- ---------

 250 Retail Sales.com  Wrong URL  9 07-MAY-06

 260 Recruiting.com  Wrong URL  9 07-MAY-06

 270 Payroll.com  Wrong URL  9 07-MAY-06

This statement updated 3 rows with the same new values on all 3 rows.