MySQL Trigger Learning

Create a Trigger

Grammar:

Create TRIGGER Trigger Name

Create trigger Xiaoshou_update_trigger after update on Xiaoshou for each row begin update Jiangjin set xiaoshouer= (select SUM (Taoshu*danjia) from Xiaoshou where Userid=new.userid and Month=new.month), jiangjin= (select sum (taoshu* Xiaoshou.danjia*ticheng) from House,xiaoshou where Userid=new.userid and Month=new.month and Houseid=id) where userid= New.userid and Month=new.month;delete from Jiangjin where Xiaoshouer<500;delete from Jiangjin where xiaoshouer<500 ; end