联表更新

mysql关联多表进行update更新操作

UPDATE Track

INNER JOIN MV

ON Track.trkid=MV.mvid

SET Track.is_show=MV.is_show

WHERE trkid<6

等同于

UPDATE Track,MV

SET Track.is_show=MV.is_show

WHERE Track.trkid=MV.mvid and trkid<6

UPDATE admin AS a LEFT JOIN admin_role_user as r ON a.admin_id = r.admin_id 
SET duty_id = 1 WHERE r.role_id = 2