我有以下两个表：
Products
+--------------------------+--------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+--------------------------+--------------+------+-----+---------+-------+
| id | int(6) | NO | PRI | NULL | |
| productName | varchar(255) | YES | | NULL | |
| landColour | varchar(255) | YES | | NULL | |
+--------------------------+--------------+------+-----+---------+-------+
Skus
+--------------+---------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+--------------+---------------+------+-----+---------+-------+
| id | int(11) | NO | PRI | NULL | |
| product_id | int(11) | NO | MUL | NULL | |
| colour | varchar(255) | NO | MUL | NULL | |
| fit | varchar(255) | NO | MUL | NULL | |
| size | decimal(10,1) | NO | MUL | NULL | |
| stock_status | varchar(255) | NO | MUL | NULL | |
| image | varchar(255) | NO | | NULL | |
+--------------+---------------+------+-----+---------+-------+
Product Data
+----+--------------+------------+
| id | productName | landColour |
+----+--------------+------------+
| 1 | Running Shoe | Red |
| 2 | Smart Shoe | Green |
| 3 | Casual Shoe | Blue |
+----+--------------+------------+
Sku Data
+----+------------+--------+--------------+------+--------------+----------------+
| id | product_id | colour | fit | size | stock_status | image |
+----+------------+--------+--------------+------+--------------+----------------+
| 1 | 1 | Red | Standard Fit | 5 | In-Stock | /img/img1.jpg |
| 2 | 1 | Green | Standard Fit | 5 | In-Stock | /img/img2.jpg |
| 3 | 1 | Blue | Standard Fit | 5 | In-Stock | /img/img3.jpg |
| 4 | 1 | Red | Standard Fit | 6 | Out-of-Stock | /img/img4.jpg |
| 5 | 1 | Green | Standard Fit | 6 | In-Stock | /img/img5.jpg |
| 6 | 1 | Blue | Standard Fit | 6 | In-Stock | /img/img6.jpg |
| 7 | 2 | Red | Standard Fit | 5 | Out-of-Stock | /img/img7.jpg |
| 8 | 2 | Green | Standard Fit | 5 | Out-of-Stock | /img/img8.jpg |
| 9 | 2 | Blue | Standard Fit | 5 | Out-of-Stock | /img/img9.jpg |
| 10 | 2 | Red | Standard Fit | 6 | In-Stock | /img/img10.jpg |
| 11 | 2 | Green | Standard Fit | 6 | Out-of-Stock | /img/img11.jpg |
| 12 | 2 | Blue | Standard Fit | 6 | In-Stock | /img/img12.jpg |
| 13 | 3 | Red | Standard Fit | 5 | In-Stock | /img/img13.jpg |
| 14 | 3 | Green | Standard Fit | 5 | In-Stock | /img/img14.jpg |
| 15 | 3 | Blue | Standard Fit | 5 | In-Stock | /img/img15.jpg |
| 16 | 3 | Red | Standard Fit | 6 | In-Stock | /img/img16.jpg |
| 17 | 3 | Green | Standard Fit | 6 | In-Stock | /img/img17.jpg |
| 18 | 3 | Blue | Standard Fit | 6 | In-Stock | /img/img18.jpg |
+----+------------+--------+--------------+------+--------------+----------------+
Desired Results
+------------+--------+--------+------+----------------+
| product_id | sku_id | colour | size | image |
+------------+--------+--------+------+----------------+
| 1 | 1 | Red | 5 | /img/img1.jpg |
| 1 | 5 | Green | 6 | /img/img5.jpg |
| 2 | 10 | Red | 6 | /img/img10.jpg |
| 3 | 15 | Blue | 5 | /img/img15.jpg |
| 3 | 18 | Blue | 6 | /img/img18.jpg |
+------------+--------+--------+------+----------------+
我正在尝试检索fit = 'Standard Fit'和stock_status = 'In-Stock'按大小分组的所有skus，但如果skus.colour字段与products.landColour列匹配，那么这是我首选的记录。我们的目标是，对于每种产品，我都会有库存记录，每种尺寸都有库存，最好是与地面颜色相同的颜色。这是我试过的几乎是正确但不完全的，有些记录即使有库存也没有退货：
SELECT
p.productName AS name,
p.id AS product_id,
IF(s1.size IS NULL, s2.size, s1.size) AS size,
IF(s1.image IS NULL, s2.image, s1.image) AS image,
IF(s1.fit IS NULL, s2.fit, s1.fit) AS fit
FROM products p
LEFT JOIN skus s1 ON
p.id = s1.product_id
AND s1.stock_status = 'In-Stock'
AND s1.colour = p.landColour AND
s1.fit = 'Standard Fit'
LEFT JOIN skus s2 ON
p.id = s2.product_id
AND s2.stock_status = 'In-Stock'
AND s2.fit = 'Standard Fit'
GROUP BY size
HAVING ( image IS NOT NULL AND size IS NOT NULL )
答案 0 :(得分：0)
我没有完全按照你要做的去做。然而，这是非常可疑的：
GROUP BY size
我怀疑你想要：
GROUP BY p.productName, p.id
答案 1 :(得分：0)
我会使用SINGLE加入并添加一列来表示您的＆＃34;首选＆＃34;条目。然后您的订单可以基于所有首选推送到顶部和所有其他人跟随。在这种情况下，对于每个产品，我只有一个标志，如果找到首选颜色，它得到1（以后排序），否则2在＃1首选之后。
SELECT
p.productName AS name,
p.id product_id,
s1.size,
s1.image,
s1.fit,
if( s1.colour = p.landColour, 1, 2 ) as PreferredFlag
FROM
products p
LEFT JOIN skus s1
ON p.id = s1.product_id
AND s1.stock_status = 'In-Stock'
AND s1.fit = 'Standard Fit'
GROUP BY
size,
if( s1.colour = p.landColour, 1, 2 ) as PreferredFlag
HAVING
image IS NOT NULL
AND size IS NOT NULL
order by
if( s1.colour = p.landColour, 1, 2 ),
size
现在，除了大小之外，您没有进行任何真正保证组合的聚合，这只会导致任何给定大小的第一个产品名称和ID符合条件。您可能实际上需要调整到类似下面的内容。在这种情况下，我得到一个与所需颜色匹配的计数的SUM作为首选标志COUNTER。但也有一个COUNT，其中有多少给定的产品名称和尺寸实际可用，无论颜色如何。
最终的ORDER BY基于......如果匹配颜色的总数是> 0，然后它得到1，否则为2用于排序目的，然后按大小排序。
SELECT
p.productName AS name,
p.id product_id,
s1.size,
s1.image,
s1.fit,
COUNT(*) as NumberAvailable,
SUM( if( s1.colour = p.landColour, 1, 0 )) as PreferredFlag
FROM
products p
LEFT JOIN skus s1
ON p.id = s1.product_id
AND s1.stock_status = 'In-Stock'
AND s1.fit = 'Standard Fit'
GROUP BY
p.productName
HAVING
image IS NOT NULL
AND size IS NOT NULL
order by
if( SUM( if( s1.colour = p.landColour, 1, 0 )) > 0, 1, 2 ) as PreferredFlag,
size