摘要:
方式一: SELECTcount(status = 0 OR NULL) AS a,count(status = 1 OR NULL) AS b,count(status = 2 OR NULL) AS c,count(status = 3 OR NULL) AS d,count(status = 阅读全文
摘要:
语法: create trigger triggerName after/before insert/update/delete on 表名 for each row #这句话在mysql是固定的 begin sql语句; end; 例子: DROP TRIGGER IF EXISTS `categ 阅读全文