由学生学号查询该学生对应的课表--查询函数

 1 CREATE DEFINER=`root`@`localhost` PROCEDURE `NewProc`(IN `学号` VARCHAR(15))
 2 BEGIN
 3     START TRANSACTION;
 4         SET @sql1 = CONCAT('SELECT `班级` INTO @classname FROM `2018-9-30在校学生名单` WHERE `学号`=',`学号`,';');
 5       prepare stmt from @sql1;  -- 预处理需要执行的动态SQL，
 6         EXECUTE stmt;
 7         deallocate prepare stmt;     -- 释放掉预处理段
 8 
 9 
10         set @sql2 = CONCAT('SELECT * FROM ',@classname,';');
11         prepare stmt from @sql2;  -- 预处理需要执行的动态SQL，
12         EXECUTE stmt;
13         deallocate prepare stmt;     -- 释放掉预处理段
14   COMMIT;
15 END