MySql创建函数

首先需要查看一下创建函数的功能是否开启：

 

X:/proper/mysql/bin>mysql -h localhost -u root -p
Enter password: **********
Welcome to the MySQL monitor.  Commands end with ; or /g.
Your MySQL connection id is 12 to server version: 5.0.22-community-nt-log

Type 'help;' or '/h' for help. Type '/c' to clear the buffer.

mysql> show variables like '%func%';

+-----------------------------------------+-------+
| Variable_name                            | Value |
+-----------------------------------------+-------+
| log_bin_trust_function_creators | ON    |
+-----------------------------------------+-------+
1 row in set (0.02 sec)

 

如果Value处值为OFF，则需将其开启。

mysql> set global log_bin_trust_function_creators=1;

 

创建函数时，先选择数据库，

 

mysql> use xxx;
Database changed

 

delimiter $$是设置 $$为命令终止符号，代替分号，因为分号在begin...end中会用到；

 

mysql> delimiter $$

 

mysql> create function test(t varchar(255))
    -> returns varchar(255)
    -> begin
    -> return left(t,1);
    -> end
    -> $$
Query OK, 0 rows affected (0.13 sec)

 

函数创建成功后需恢复分号为命令终止符号。

 

mysql> delimiter ;

 

测试：

 

mysql> select test('alpha');
+----------------+
| test('alpha') |
+---------------+
| a                 |
+---------------+
1 row in set (0.02 sec)

 

删除函数：

 

mysql> drop function test;
Query OK, 0 rows affected (0.11 sec)