create trigger triggerName?
?after/before insert/update/delete on tableName
?for each row?? --這句話在mysql是固定的?
?begin?
??? sql語句;?
?end;?

?

如下在插入之前自動生成座位號

DROP TRIGGER IF EXISTS `pxlb_zwh_insert`;?
CREATE TRIGGER `pxlb_zwh_insert`???
BEFORE INSERT ON `dj_pxlb`???????????
FOR EACH ROW
begin
IF new.zwh IS NULL OR new.zwh < 1 THEN
???? SET new.zwh = (select IFNULL(max(t1.zwh),0)+1 from `dj_pxlb` as t1 where t1.ccbh=new.ccbh);
END IF;
end;?

?

?

?

DROP TRIGGER IF EXISTS t_make_data;?
CREATE TRIGGER t_make_data?
BEFORE INSERT ON t_tab1?
FOR EACH ROW
BEGIN??
DECLARE number_rand BIGINT(20) DEFAULT 4000 ;??? --聲明變量
SET number_rand = (SELECT CAST(RAND()*300+300 AS signed) AS rand);
SET new.number_rand = number_rand;
END;

轉載于:https://www.cnblogs.com/gaobo543013306/p/9871453.html

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