MySQL使用存储过程，光标的使用的简单示例

存储过程一直没仔细学，今天为了完成实验，老老实实看了书，在网上看了不少东西，想起来简单，实现起来不容易啊，经过一个多小时的攻坚克难，总算实现了老师的要求，把完美的命令过程贴在下面，用于以后的改进

问题描述：

　　现有三张表，教职工，转换，论文，教职工记录学院教职工的基本信息，这里要用的是姓名和所属系别，转换是教职工中文名和英文名的转换关系，论文是教职工所发表的论文信息，其中的作者数据可能是中文名也可能是英文名，要实现的是写一个存储过程实现以系中心为参数，查找各系中心发表的论文数。

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mysql> use sstest;
Database changed
mysql> desc 教职工;
+------------+--------------+------+-----+---------+----------------+
| Field      | Type         | Null | Key | Default | Extra          |
+------------+--------------+------+-----+---------+----------------+
| 教职工ID   | int(11)      | NO   | PRI | NULL    | auto_increment |
| 工号       | mediumint(9) | YES  |     | NULL    |                |
| 姓名       | varchar(30)  | NO   |     | NULL    |                |
| 性别       | varchar(5)   | NO   |     | NULL    |                |
| 系中心     | varchar(40)  | YES  |     | NULL    |                |
| 职务       | varchar(30)  | YES  |     | NULL    |                |
| 职称       | varchar(30)  | YES  |     | NULL    |                |
| 退休前职务 | varchar(30)  | NO   |     | NULL    |                |
| 调离前职务 | varchar(50)  | YES  |     | NULL    |                |
| 调离前所属 | varchar(50)  | YES  |     | NULL    |                |
| 固定电话   | varchar(11)  | YES  |     | NULL    |                |
| 移动电话   | int(11)      | YES  |     | NULL    |                |
| 出生日期   | date         | YES  |     | NULL    |                |
| 电子邮件   | varchar(30)  | YES  |     | NULL    |                |
| 备注       | varchar(50)  | YES  |     | NULL    |                |
+------------+--------------+------+-----+---------+----------------+
15 rows in set (0.04 sec)

mysql> desc 转换;
+--------+-------------+------+-----+---------+-------+
| Field  | Type        | Null | Key | Default | Extra |
+--------+-------------+------+-----+---------+-------+
| 英文名 | varchar(30) | YES  |     | NULL    |       |
| 中文名 | varchar(30) | YES  |     | NULL    |       |
+--------+-------------+------+-----+---------+-------+
2 rows in set (0.00 sec)

mysql> desc 论文;
+--------+--------------+------+-----+---------+----------------+
| Field  | Type         | Null | Key | Default | Extra          |
+--------+--------------+------+-----+---------+----------------+
| 成果ID | int(11)      | NO   | PRI | NULL    | auto_increment |
| 作者   | varchar(100) | NO   |     | NULL    |                |
| 题名   | varchar(160) | YES  |     | NULL    |                |
| 刊名   | varchar(160) | YES  |     | NULL    |                |
+--------+--------------+------+-----+---------+----------------+
4 rows in set (0.00 sec)

mysql> delimiter //
mysql> drop procedure if exists `get_count_of_paper_of_major`;//
Query OK, 0 rows affected (0.04 sec)

mysql> create procedure get_count_of_paper_of_major(in major_name varchar(40), out count_of_papers int)
    -> reads sql data
    -> begin
    -> declare cnt int default 0;
    -> declare tmp int default 0;
    -> declare tmp_name varchar(30) default "";
    -> declare mycursor cursor for select 英文名 from 教职工,转换 where 教职工.系中心=major_name and 转换.中文名=教职工.姓名;
    -> DECLARE CONTINUE HANDLER FOR SQLSTATE '02000' SET tmp_name = NULL;
    ->
    -> open mycursor;
    -> fetch mycursor into tmp_name;
    -> while(tmp_name is not null)
    -> do
    ->  select count(*) from 论文 where 作者=tmp_name into tmp;
    ->  set cnt=cnt+tmp;
    ->  set tmp=0;
    ->  fetch mycursor into tmp_name;
    -> end while;
    -> close mycursor;
    -> set count_of_papers = cnt;
    -> end
    -> //
Query OK, 0 rows affected (0.00 sec)

mysql> delimiter ;
mysql> call get_count_of_paper_of_major('软件工程系', @count_of_papers);
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql> select @count_of_papers;
+------------------+
| @count_of_papers |
+------------------+
|               21 |
+------------------+
1 row in set (0.00 sec)

mysql> call get_count_of_paper_of_major('数字媒体技术系', @count_of_papers);
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql> select @count_of_papers;
+------------------+
| @count_of_papers |
+------------------+
|                0 |
+------------------+
1 row in set (0.00 sec)

mysql> call get_count_of_paper_of_major('信息安全系', @count_of_papers);
Query OK, 0 rows affected, 1 warning (0.00 sec)

mysql> select @count_of_papers;
+------------------+
| @count_of_papers |
+------------------+
|                2 |
+------------------+
1 row in set (0.00 sec)

mysql>

对比以前写的语句，恩，好像没有问题

 

不得不说MySQL在存储过程和触发器还是和MS SQL Server，DB2，Oracle的差距还很大，很多的功能就MySQL没有实现，实现了的也相对比较麻烦，嗯，不管怎么样，希望MySQL越做越好，以开源战胜商业！加油