mysql自定义函数怎么写？

mysql>CREATE FUNCTION HelloWorld4()

->RETURNS VARCHAR(20)

->BEGIN

->  RETURN 'Hello World!'

->END

->//

Query OK, 0 rows affected (0.00 sec)

mysql>select HelloWorld4() //

+---------------+

| HelloWorld4() |

+---------------+

| Hello World!  |

+---------------+

1 row in set (0.00 sec) ...展开mysql>CREATE FUNCTION HelloWorld4()

->RETURNS VARCHAR(20)

->BEGIN

->  RETURN 'Hello World!'

->END

->//

Query OK, 0 rows affected (0.00 sec)

mysql>select HelloWorld4() //

+---------------+

| HelloWorld4() |

+---------------+

| Hello World!  |

+---------------+

1 row in set (0.00 sec)

mysql>CREATE FUNCTION HelloWorld4()

->RETURNS VARCHAR(20)

->BEGIN

-> RETURN 'Hello World!'

->END

->//

Query OK, 0 rows affected (0.00 sec)

mysql>select HelloWorld4() //

+---------------+

| HelloWorld4() |

+---------------+

| Hello World! |

+---------------+

1 row in set (0.00 sec)

如果你会其它数据库的话， 那么看看那个 SQL 存储过程编写 参考手册 对你会有些帮助。

function get_client_ip() {

$ip = $_SERVER['REMOTE_ADDR']

if (isset($_SERVER['HTTP_CLIENT_IP']) &&preg_match('/^([0-9]{1,3}\.){3}[0-9]{1,3}$/', $_SERVER['HTTP_CLIENT_IP'])) {

$ip = $_SERVER['HTTP_CLIENT_IP']

} elseif(isset($_SERVER['HTTP_X_FORWARDED_FOR']) AND preg_match_all('#\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}#s', $_SERVER['HTTP_X_FORWARDED_FOR'],

$matches)) {

foreach ($matches[0] AS $xip) {

if (!preg_match('#^(10|172\.16|192\.168)\.#', $xip)) {

$ip = $xip

break

}

}

}

return $ip

}

$conn=mysql_connect("localhost","root","123412341234")

mysql_select_db("shujuku",$conn)

$query="INSERT INTO ip(`id`,`userip`)VALUES(null,'".get_client_ip()."')"

$result=mysql_query($query)

是不是应该这样写法的啊

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