weixin_44713908的博客

Select fun_variable('rr1','123','5555') ；调用语句：CREATE FUNCTION fun_variable()RETURNS int(20)BEGINDECLARE msg VARCHAR(20);if not exists (SELECT * FROM class WHERE `name`=name1) then ...

以下语句在查询中完成语句：CREATE PROCEDURE tttt(name1 varchar(10),number varchar(11),newname varchar(10))BEGIN if not exists (SELECT * FROM class WHERE `name`=name1) then Insert into class(...

INSERT into class(`name`,`number`) select 'rr12','123' FROM DUAL WHERE NOT EXISTS(SELECT * FROM class WHERE `name` = 'rr12');