MySQL 练习题16.1

MySQL 练习题16.1_其他

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1…创建存储过程,使用流程控制语句,编写SQL语句,要求以下:
(1)实现1-10之间数字的遍历。
(2)当数字大于10退出遍历。
(3)数字在1-10之间时,遍历数字并输出。

方法一:

mysql> delimiter //
mysql> create procedure proc10()
    -> begin
    -> declare id int default 0;
    -> my_loop:loop
    -> set id=id+1;
    -> if id>10 then leave my_loop;
    -> end if;
    -> select id;
    -> end loop my_loop;
    -> end //

方法二:

mysql> create procedure proc10()
    -> begin
    -> declare i int default 1;
    -> while i<=10 do
    -> select i;
    -> set i=i+1;
    -> end while;
    -> end //
Query OK, 0 rows affected (0.00 sec)

2…创建的学生表及数据,创建存储过程,定义两个变量,分别接收tom的成绩和性别,输出这两个变量,调用并删除存储过程

mysql> select * from student;
+----+------+-------+--------+
| id | name | grade | gender |
+----+------+-------+--------+
|  1 | tom  |    60 ||
|  2 | jack |    70 ||
|  3 | rose |    90 ||
|  4 | lucy |   100 ||
+----+------+-------+--------+
4 rows in set (0.00 sec)
mysql> delimiter //
mysql> create procedure proc10()
    -> begin
    -> declare s_grade float;
    -> declare s_gender char(4);
    -> select grade,gender into s_grade,s_gender from student where name='tom';
    -> select s_grade,s_gender;
    -> end //
Query OK, 0 rows affected (0.00 sec)

mysql> call proc10() //
+---------+----------+
| s_grade | s_gender |
+---------+----------+
|      60 ||
+---------+----------+
1 row in set (0.02 sec)

Query OK, 0 rows affected (0.02 sec)