mysql存储过程之返回多个值的⽅法⽰例
本⽂实例讲述了mysql存储过程之返回多个值的⽅法。分享给⼤家供⼤家参考，具体如下：
mysql存储函数只返回⼀个值。要开发返回多个值的存储过程，需要使⽤带有INOUT或OUT参数的存储过程。咱们先来看⼀个orders表它的结构：
mysql> desc orders;
+----------------+-------------+------+-----+---------+-------+
| Field    | Type    | Null | Key | Default | Extra |
+----------------+-------------+------+-----+---------+-------+
| orderNumber  | int(11)  | NO  | PRI | NULL  |    |
| orderDate  | date    | NO  |  | NULL  |    |
| requiredDate  | date    | NO  |  | NULL  |    |
| shippedDate  | date    | YES |  | NULL  |    |
| status    | varchar(15) | NO  |  | NULL  |    |
| comments    | text    | YES |  | NULL  |    |
| customerNumber | int(11)  | NO  | MUL | NULL  |    |
+----------------+-------------+------+-----+---------+-------+
7 rows in set
然后嘞，咱们来看⼀个存储过程，它接受客户编号，并返回发货(shipped)，取消(canceled)，解决(resolved)和争议(disputed)的订单总数：
DELIMITER $$
CREATE PROCEDURE get_order_by_cust(
IN cust_no INT,
OUT shipped INT,
OUT canceled INT,
OUT resolved INT,
OUT disputed INT)
BEGIN
-- shipped
SELECT
count(*) INTO shipped
FROM
orders
WHERE
customerNumber = cust_no
AND status = 'Shipped';
-
- canceled
SELECT
count(*) INTO canceled
FROM
orders
WHERE
customerNumber = cust_no
AND status = 'Canceled';
-- resolved
SELECT
count(*) INTO resolved
FROM
orders
WHERE
customerNumber = cust_no
AND status = 'Resolved';
-- disputed
SELECT
count(*) INTO disputed
FROM
orders
WHERE
customerNumber = cust_no
AND status = 'Disputed';
END
其实，除IN参数之外，存储过程还需要4个额外的OUT参数：shipped, canceled, resolved 和 disputed。在存储过程中，使⽤带有count函数的select语句根据订单状态获取相应的订单总数，并将其分配给相应的参数。按着上⾯的sql，我们如果要使⽤get_order_by_cust存储过程，可以传递客户编号和四个⽤户定义的变量来获取输出值。执⾏存储过程后，我们再使⽤SELECT语句输出变量值：
+----------+-----------+-----------+-----------+
| @shipped | @canceled | @resolved | @disputed |
+----------+-----------+-----------+-----------+
|    22 |    0 |    1 |    1 |
+----------+-----------+-----------+-----------+
1 row in set
结合实际应⽤，我们再来看下从PHP程序中调⽤返回多个值的存储过程：
<?php
/**
* Call stored procedure that return multiple values
* @param $customerNumber
*/
function call_sp($customerNumber)
{
try {
$pdo = new PDO("mysql:host=localhost;dbname=yiibaidb", 'root', '123456');
/
/ execute the stored procedure
$sql = 'CALL get_order_by_cust(:no,@shipped,@canceled,@resolved,@disputed)';
$stmt = $pdo->prepare($sql);
$stmt->bindParam(':no', $customerNumber, PDO::PARAM_INT);
$stmt->execute();
$stmt->closeCursor();
// execute the second query to get values from OUT parameterrows函数的使用方法及实例
$r = $pdo->query("SELECT @shipped,@canceled,@resolved,@disputed")
->fetch(PDO::FETCH_ASSOC);
if ($r) {
printf('Shipped: %d, Canceled: %d, Resolved: %d, Disputed: %d',
$r['@shipped'],
$r['@canceled'],
$r['@resolved'],
$r['@disputed']);
}
} catch (PDOException $pe) {
die("Error occurred:" . $pe->getMessage());
}
}
call_sp(141);
上述代码中，在@符号之前的⽤户定义的变量与数据库连接相关联，因此它们可⽤于在调⽤之间进⾏访问。好啦，本次分享就到这⾥了。
更多关于MySQL相关内容感兴趣的读者可查看本站专题：《》、《》、《》、《》及《》
希望本⽂所述对⼤家MySQL数据库计有所帮助。