MySQL.PROCEDURE.使用存储过程

mysql> DELIMITER //
mysql> CREATE PROCEDURE productpricing()
    -> BEGIN
    -> SELECT AVG(prod_price) AS priceaverage
    -> FROM products;
    -> END//
Query OK, 0 rows affected (0.00 sec)

mysql> DELIMITER ;
mysql> CALL productpricing();
+--------------+
| priceaverage |
+--------------+
|    16.133571 |
+--------------+
1 row in set (0.00 sec)

Query OK, 0 rows affected (0.00 sec)

mysql> DROP PROCEDURE productpricing;
Query OK, 0 rows affected (0.00 sec)

mysql> DELIMITER //
mysql> CREATE PROCEDURE productpricing(
    -> OUT pl DECIMAL(8,2),
    -> OUT ph DECIMAL(8,2),
    -> OUT pa DECIMAL(8,2)
    -> )
    -> BEGIN
    -> SELECT MIN(prod_price)
    -> INTO pl
    -> FROM products;
    -> SELECT MAX(prod_price)
    -> INTO ph
    -> FROM products;
    -> SELECT AVG(prod_price)
    -> INTO pa
    -> FROM products;
    -> END//
Query OK, 0 rows affected (0.00 sec)
mysql> DELIMITER ;
mysql> CALL productpricing(@pricelow, @pricehigh, @priceaverage);
Query OK, 1 row affected, 1 warning (0.00 sec)
mysql> SELECT @priceaverage;
+---------------+
| @priceaverage |
+---------------+
|         16.13 |
+---------------+
1 row in set (0.00 sec)

mysql> SELECT @pricehigh, @pricelow, @priceaverage;
+------------+-----------+---------------+
| @pricehigh | @pricelow | @priceaverage |
+------------+-----------+---------------+
|      55.00 |      2.50 |         16.13 |
+------------+-----------+---------------+

mysql> DROP PROCEDURE productpricing;
Query OK, 0 rows affected (0.00 sec)

mysql> DELIMITER //
mysql> CREATE PROCEDURE ordertotal(
    -> IN onumber INT,
    -> OUT ototal DECIMAL(8,2)
    -> )
    -> BEGIN
    -> SELECT SUM(item_price * quantity)
    -> FROM orderitems
    -> WHERE order_num = onumber
    -> INTO ototal;
    -> END//
Query OK, 0 rows affected (0.00 sec)

or

mysql> DELIMITER //
mysql> CREATE PROCEDURE ordertotal(
    -> IN onumber INT,
    -> OUT ototal DECIMAL(8,2)
    -> )
    -> BEGIN
    -> SELECT SUM(item_price * quantity)
    -> INTO ototal
    -> FROM orderitems
    -> WHERE order_num = onumber;
    -> END//
Query OK, 0 rows affected (0.00 sec)

mysql> DELIMITER ;
mysql> CALL ordertotal(20005, @total);
Query OK, 1 row affected (0.00 sec)

mysql> SELECT @total;
+--------+
| @total |
+--------+
| 149.87 |
+--------+
1 row in set (0.00 sec)

mysql> CALL ordertotal(20009, @total);
Query OK, 1 row affected (0.00 sec)

mysql> SELECT @total;
+--------+
| @total |
+--------+
|  38.47 |
+--------+

mysql> DROP PROCEDURE ordertotal;
Query OK, 0 rows affected (0.00 sec)

mysql> -- Name; order total
mysql> -- Parameters: onumber = order number
mysql> --             taxable = 0 if not taxable, 1 if taxable
mysql> --             ototal  = order total variable
mysql>
mysql> DELIMITER //
mysql> CREATE PROCEDURE ordertotal(
    -> IN onumber INT,
    -> IN taxable BOOLEAN,
    -> OUT ototal DECIMAL(8,2)
    -> ) COMMENT ‘Obtain order total, optionally adding tax‘
    -> BEGIN
    -> -- Declare variable for total
    -> DECLARE total DECIMAL(8,2);
    -> -- Declare tax percentage
    -> DECLARE taxrate INT DEFAULT 6;
    ->
    -> -- Get the order total
    -> SELECT SUM(item_price * quantity)
    -> FROM orderitems
    -> WHERE order_num = onumber
    -> INTO total;
    ->
    -> -- Is this taxable?
    -> IF taxable THEN
    ->    -- Yes, so add taxrate to the total
    ->    SELECT total + (total / 100 * taxrate) INTO total;
    -> END IF;
    ->    -- And finally, save to out variable
    ->    SELECT total INTO ototal;
    -> END//
Query OK, 0 rows affected (0.00 sec)

mysql> DELIMITER ;

mysql> CALL ordertotal(20005, 0, @total);
Query OK, 1 row affected (0.00 sec)

mysql> SELECT @total;
+--------+
| @total |
+--------+
| 149.87 |
+--------+

mysql> CALL ordertotal(20005, 1, @total);
Query OK, 1 row affected, 1 warning (0.00 sec)

mysql> SELECT @total;
+--------+
| @total |
+--------+
| 158.86 |
+--------+

SHOW CREATE PROCEDURE ordertotal;
+------------+--------------------------------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------------+----------------------+--------------------+
| Procedure  | sql_mode                                   | Create Procedure                                                                                                                                                                                                                                                                                                                                                                                                                                                      | character_set_client | collation_connection | Database Collation |
+------------+--------------------------------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------------+----------------------+--------------------+
| ordertotal | STRICT_TRANS_TABLES,NO_ENGINE_SUBSTITUTION | CREATE DEFINER=`root`@`localhost` PROCEDURE `ordertotal`(
IN onumber INT,
IN taxable BOOLEAN,
OUT ototal DECIMAL(8,2)
)
    COMMENT ‘Obtain order total, optionally adding tax‘
BEGIN

DECLARE total DECIMAL(8,2);

DECLARE taxrate INT DEFAULT 6;

SELECT SUM(item_price * quantity)
FROM orderitems
WHERE order_num = onumber
INTO total;

IF taxable THEN

   SELECT total + (total / 100 * taxrate) INTO total;
END IF;

   SELECT total INTO ototal;
END | utf8                 | utf8_general_ci      | utf8_unicode_ci    |
+------------+--------------------------------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+----------------------+----------------------+--------------------+
1 row in set (0.00 sec)

mysql> SHOW PROCEDURE STATUS LIKE ‘ordertotal‘;
+------------+------------+-----------+----------------+---------------------+---------------------+---------------+-------------------------------------------+----------------------+----------------------+--------------------+
| Db         | Name       | Type      | Definer        | Modified            | Created             | Security_type | Comment                                   | character_set_client | collation_connection | Database Collation |
+------------+------------+-----------+----------------+---------------------+---------------------+---------------+-------------------------------------------+----------------------+----------------------+--------------------+
| learnmysql | ordertotal | PROCEDURE | root@localhost | 2015-06-09 11:42:48 | 2015-06-09 11:42:48 | DEFINER       | Obtain order total, optionally adding tax | utf8                 | utf8_general_ci      | utf8_unicode_ci    |
+------------+------------+-----------+----------------+---------------------+---------------------+---------------+-------------------------------------------+----------------------+----------------------+--------------------+
1 row in set (0.01 sec)