MySQL：是否可以合并我的MIN（）和MAX（）查询？

Question

这是我目前正在做的简化版本。

一种）

SELECT id, foreign_key_id, type, quantity, MAX(price) AS price // <--- Max
FROM quotes
WHERE type = 'tier 1'                                          // <--- Equal
AND prod_id_requested = 12345

B）

SELECT id, foreign_key_id, type, quantity, MAX(price) AS price // <--- Max
FROM quotes
WHERE type != 'tier 1'                                         // <--- NOT equal
AND prod_id_requested = 12345

C）

SELECT id, foreign_key_id, type, quantity, MIN(price) AS price // <--- Min
FROM quotes
WHERE type = 'tier 1'                                          // <--- Equal
AND prod_id_requested = 12345

D）

SELECT id, foreign_key_id, type, quantity, MIN(price) AS price // <--- Min
FROM quotes
WHERE type != 'tier 1'                                         // <--- NOT equal
AND prod_id_requested = 12345

我有什么好方法可以节省一些资源，也许可以将它们组合成更少的查询？
还是这差不多就是这样做的方式？

[ 更新 ]
以下是一些示例数据：

CREATE TABLE IF NOT EXISTS `quote_item` (
  `id` int(2) unsigned NOT NULL AUTO_INCREMENT,
  `quote_id` int(2) unsigned NOT NULL,
  `product_id_quoted` int(3) unsigned NOT NULL,
  `product_id_requested` int(3) unsigned NOT NULL,
  `type` varchar(52) DEFAULT NULL,
  `price` float(10,4) NOT NULL,
  `quantity` int(9) unsigned NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=MyISAM  DEFAULT CHARSET=utf8 AUTO_INCREMENT=1 ;

INSERT INTO `quote_item` (`id`, `quote_id`, `product_id_quoted`, `product_id_requested`, `type`, `price`, `quantity`) VALUES
(1, 1, 12, 12, 'tier 1', 0.0100, 100),
(2, 2, 1, 12, 'tier 3', 0.0038, 8200),
(3, 2, 13, 12, 'tier 2', 0.0041, 10000),
(4, 3, 7, 14, 'tier 1', 0.0060, 25000),
(5, 3, 8, 12, NULL, 0.0180, 250),
(6, 3, 9, 15, NULL, 0.0019, 5000),
(7, 4, 12, 12, NULL, 0.0088, 7500),
(8, 4, 16, 12, 'tier 1', 0.0040, 10000),
(9, 5, 12, 9, 'tier 2', 0.0089, 1200),
(10, 5, 12, 12, 'tier 1', 0.0072, 6400);

最终，我们希望将所有数据打包到一个数组中。
当前，我们从每个查询（没有分组）中获得一行，其中具有最小值的单行具有实际的ID ， Qty 等 ...，具有最大值的单行具有相同的信息，然后按“类型”类别创建数组。
例如：

$flash_report = array(
    'tier1' => array(
        'qty' => array(
            'min' => array(
                'id' => 1
                ,'quote_id' => 1
                ,'price' => 0.01
                ,'quantity' => 100
                )
            ,'max' => array(
                'id' => 8
                ,'quote_id' => 4
                ,'price' => 0.004
                ,'quantity' => 10000
                )
            ,'sum' => array(
                'value' => 16500
                ,'count' => 3
                )
        )
        ,'price' => array(
            'min' => array(
                'id' => 8
                ,'quote_id' => 4
                ,'price' => 0.004
                ,'quantity' => 10000
                )
            ,'max' => array(
                'id' => 1
                ,'quote_id' => 1
                ,'price' => 0.01
                ,'quantity' => 100
                )
        )
    )
    ,'other' => array(
        'qty' => array(
            'min' => array(
                'id' => 5
                ,'quote_id' => 3
                ,'price' => 0.018
                ,'quantity' => 250
                )
            ,'max' => array(
                'id' => 3
                ,'quote_id' => 2
                ,'price' => 0.0041
                ,'quantity' => 10000
                )
            ,'sum' => array(
                'value' => 25950
                ,'count' => 4
                )
        )
        ,'price' => array(
            'min' => array(
                'id' => 2
                ,'quote_id' => 2
                ,'price' => 0.0038
                ,'quantity' => 8200
                )
            ,'max' => array(
                'id' => 5
                ,'quote_id' => 3
                ,'price' => 0.018
                ,'quantity' => 250
                )
        )
    )
)

[ / UPDATE ]

现在，我从单个查询中获取所有数据，然后将所有数据组装成一个大整数数组。
我想那里一定是一个更好的方式来做到这一点:)

Answer 1

您可以将所有内容组合在一起：

SELECT "equal" as condition,
       MAX(price) AS max_price,
       MIN(price) AS min_price
  FROM quotes
 WHERE type = 'tier 1'
 GROUP BY 1
UNION
SELECT "not_equal" as condition,
       MAX(price) as max_price,
       MIN(price) as min_price
  FROM quotes
 WHERE type != "tier 1"
 GROUP BY 1

我比CASE解决方案更好（尽管它们更简洁），因为它完全符合SQL92。

我删除了id，foreign_key和qty字段，因为我不认为您打算将聚合分组在键上，并且想知道为什么还要将它们分组在qty上。

Answer 2

SELECT id, foreign_key_id, type, quantity, 
    MIN(case when type != 'tier 1' then price end) as MinNotTier1Price,
    MIN(case when type == 'tier 1' then price end) as MinTier1Price,
    MAX(case when type != 'tier 1' then price end) as MaxNotTier1Price,
    MAX(case when type == 'tier 1' then price end) as MaxTier1Price
FROM quotes 

Answer 3

SELECT id, 
       foreign_key_id, 
       type,
       quantity, 
       MAX(case when type = 'tier 1' then price else NULL end) AS price_max_eq,
       MIN(case when type = 'tier 1' then price else NULL end) AS price_min_eq,
       MAX(case when type <> 'tier 1' then price else NULL end) AS price_max_neq,
       MIN(case when type <> 'tier 1' then price else NULL end) AS price_min_neq,
FROM quotes

Answer 4

您至少可以像这样组合A和C以及B和D

SELECT id, 
       foreign_key_id, 
       type, 
       quantity, 
       MAX(price) AS max_price, 
       MIN(price) AS min_price
FROM quotes
WHERE type = 'tier 1' 
GROUP BY id, foreign_key_id, type, quantity


SELECT id, 
       foreign_key_id, 
       type, 
       quantity, 
       MAX(price) AS max_price, 
       MIN(price) AS min_price
FROM quotes
WHERE type != 'tier 1' 
GROUP BY id, foreign_key_id, type, quantity