学习mysql中case when语句的用法，代码如下：
mysql> delimiter $$mysql> CREATE PROCEDURE myProc(id int) //创建mysql存储过程 -> BEGIN -> -> CASE -> WHEN id < 2 THEN -> select 'less than 2'; -> -> WHEN id > 2 and id < 5 THEN -> select 'greater than 2 and less than 5'; -> -> WHEN id > 5 THEN -> select 'greater than 5'; -> -> END CASE; -> END$$Query OK, 0 rows affected (0.00 sec)mysql> delimiter ;mysql> call myProc(2); //调用存储过程myProcERROR 1339 (20000): Case not found for CASE statementmysql> call myProc(20);+----------------+| greater than 5 |+----------------+| greater than 5 |+----------------+1 row in set (0.00 sec)Query OK, 0 rows affected (0.00 sec)mysql> drop procedure myProc; //删除存储过程myProcQuery OK, 0 rows affected (0.00 sec)
