【数据库MySQL】练习---存储过程和函数

一、数据准备

 sch表结构：

字段名	数据类型	主键	外键	非空	唯一	自增
id	INT	是	否	是	是	否
name	VARCHAR(50)	否	否	是	否	否
glass	VARCHAR(50)	否	否	是	否	否

 sch表内容:

id	name	glass
1	xiaoming	glass 1
2	xiaojun	glass 2

1、创建sch表和emp表

#sch表
Create table sch(
Id int primary key unique,
Name varchar(50) not null,
Glass varchar(50) not null
);

#emp表
CREATE TABLE `emp`  (
  `empno` int(4) NOT NULL,
  `ename` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
  `job` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
  `mgr` int(4) NULL DEFAULT NULL,
  `hiredate` date NOT NULL,
  `sai` int(255) NOT NULL,
  `comm` int(255) NULL DEFAULT NULL,
  `deptno` int(2) NOT NULL,
  PRIMARY KEY (`empno`) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Dynamic;

 2、插入数据

#sch表
insert into sch values(1,'xiaoming','glass 1');
insert into sch values(2,'xiaojun','glass 2');

#emp表
INSERT INTO `emp` VALUES (1001, '甘宁', '文员', 1013, '2000-12-17', 8000, NULL, 20);
INSERT INTO `emp` VALUES (1002, '黛绮丝', '销售员', 1006, '2001-02-20', 16000, 3000, 30);
INSERT INTO `emp` VALUES (1003, '殷天正', '销售员', 1006, '2001-02-22', 12500, 5000, 30);
INSERT INTO `emp` VALUES (1004, '刘备', '经理', 1009, '2001-04-02', 29750, NULL, 20);
INSERT INTO `emp` VALUES (1005, '谢逊', '销售员', 1006, '2001-09-28', 12500, 14000, 30);
INSERT INTO `emp` VALUES (1006, '关羽', '经理', 1009, '2001-05-01', 28500, NULL, 30);
INSERT INTO `emp` VALUES (1007, '张飞', '经理', 1009, '2001-09-01', 24500, NULL, 10);
INSERT INTO `emp` VALUES (1008, '诸葛亮', '分析师', 1004, '2007-04-19', 30000, NULL, 20);
INSERT INTO `emp` VALUES (1009, '曾阿牛', '董事长', NULL, '2001-11-17', 50000, NULL, 10);
INSERT INTO `emp` VALUES (1010, '韦一笑', '销售员', 1006, '2001-09-08', 15000, 0, 30);
INSERT INTO `emp` VALUES (1011, '周泰', '文员', 1006, '2007-05-23', 11000, NULL, 20);
INSERT INTO `emp` VALUES (1012, '程普', '文员', 1006, '2001-12-03', 9500, NULL, 30);
INSERT INTO `emp` VALUES (1013, '庞统', '分析师', 1004, '2001-12-03', 30000, NULL, 20);
INSERT INTO `emp` VALUES (1014, '黄盖', '文员', 1007, '2002-01-23', 13000, NULL, 10);
INSERT INTO `emp` VALUES (1015, '张三', '保洁员', 1001, '2013-05-01', 80000, 50000, 50);

3、查看表数据记录

mysql> select * from sch;
+----+----------+---------+
| Id | Name     | Glass   |
+----+----------+---------+
|  1 | xiaoming | glass 1 |
|  2 | xiaojun  | glass 2 |
+----+----------+---------+
2 rows in set (0.00 sec)

mysql> select * from emp;
+-------+-----------+-----------+------+------------+-------+-------+--------+
| empno | ename     | job       | mgr  | hiredate   | sai   | comm  | deptno |
+-------+-----------+-----------+------+------------+-------+-------+--------+
|  1001 | 甘宁      | 文员      | 1013 | 2000-12-17 |  8000 |  NULL |     20 |
|  1002 | 黛绮丝    | 销售员    | 1006 | 2001-02-20 | 16000 |  3000 |     30 |
|  1003 | 殷天正    | 销售员    | 1006 | 2001-02-22 | 12500 |  5000 |     30 |
|  1004 | 刘备      | 经理      | 1009 | 2001-04-02 | 29750 |  NULL |     20 |
|  1005 | 谢逊      | 销售员    | 1006 | 2001-09-28 | 12500 | 14000 |     30 |
|  1006 | 关羽      | 经理      | 1009 | 2001-05-01 | 28500 |  NULL |     30 |
|  1007 | 张飞      | 经理      | 1009 | 2001-09-01 | 24500 |  NULL |     10 |
|  1008 | 诸葛亮    | 分析师    | 1004 | 2007-04-19 | 30000 |  NULL |     20 |
|  1009 | 曾阿牛    | 董事长    | NULL | 2001-11-17 | 50000 |  NULL |     10 |
|  1010 | 韦一笑    | 销售员    | 1006 | 2001-09-08 | 15000 |     0 |     30 |
|  1011 | 周泰      | 文员      | 1006 | 2007-05-23 | 11000 |  NULL |     20 |
|  1012 | 程普      | 文员      | 1006 | 2001-12-03 |  9500 |  NULL |     30 |
|  1013 | 庞统      | 分析师    | 1004 | 2001-12-03 | 30000 |  NULL |     20 |
|  1014 | 黄盖      | 文员      | 1007 | 2002-01-23 | 13000 |  NULL |     10 |
|  1015 | 张三      | 保洁员    | 1001 | 2013-05-01 | 80000 | 50000 |     50 |
+-------+-----------+-----------+------+------------+-------+-------+--------+
15 rows in set (0.00 sec)

二、习题

1、创建一个可以统计表格内记录条数的存储函数，函数名为count_sch()。

\d $$
Create function count_sch()
Returns int
Begin
Declare n int default 0;
Select count(*) into n from sch;
Return n;
End $$
\d;

mysql> Select count_sch();
+-------------+
| count_sch() |
+-------------+
|           2 |
+-------------+
1 row in set (0.00 sec)

2、创建一个存储过程avg_sai，有3个参数，分别是deptno，job，接收平均工资，功能查询emp表dept为30，job为销售员的平均工资。

\d $$
Create procedure avg_sai(in p1 int(2),in p2 varchar(255),out p3 int)
Begin
  Select avg(sai) into p3 from emp
    Where deptno=p1 and job=p2;
End $$
\d;

mysql> call avg_sai(30,'销售员',@a);
Query OK, 1 row affected (0.00 sec)

mysql> select @a;
+-------+
| @a    |
+-------+
| 14000 |
+-------+
1 row in set (0.00 sec)