MySql Functions

1）创建函数

CREATE DEFINER=`root`@`localhost` FUNCTION `fun_studentunum`(classname nvarchar(200)) RETURNS int(32)
BEGIN
	declare num int default 0;
    select count(1) into num from mystudent s
    inner join  myclass c on s.ClassID=c.ClassID
    where c.ClassName=classname;

	return num;
END

2）调用函数

select fun_studentunum('2班')；