我希望有人可以提供帮助，因为我已经尝试解决这个问题一段时间了，并且遇到了一个非常小的问题。
通过下面的查询，我主要尝试执行以下操作：
从订单中选择所有股票代码。
然后，查找每个股票代码存储在 STOCK_LOCATIONS 表中的所有位置。
然后，从 STOCK_LOCATIONS 表中返回一个位置。
但是，我需要交叉引用 LOCATION_DATA 表。LOCATION_DATA 表中的每个位置都有一个名为 PICK 的列，并且包含 Y 或 N。我想返回带有 Y 作为第一选择的位置，如果不存在则返回 N，如果 PICK 列中不存在 Y。
我实际上需要在 Inner Join LOCATION_DATA 查询中对结果进行排序，但这是不可能的。我尝试在 INNER JOIN 中添加一个 SELECT 语句（我相信这可能是要走的路），但未能让它工作。
任何建议表示赞赏。提前谢谢了...
SELECT
STOCK_LOCATIONS.*,
LOCATION_DATA.*,
STOCK_DATA.PHYSICAL,
ORDER_DATA.ENTRY,
ORDER_DATA.STOCK,
ORDER_DATA.ORDER_QTY,
(SELECT
COUNT(STOCK_LOCATIONS.location)
FROM STOCK_LOCATIONS
WHERE ORDER_DATA.STOCK = STOCK_LOCATIONS.sku
GROUP BY STOCK_LOCATIONS.sku
HAVING COUNT(STOCK_LOCATIONS.sku) > 1
) AS RowCount
FROM ORDER_DATA
INNER JOIN STOCK_DATA
ON ORDER_DATA.STOCK = STOCK_DATA.STOCK_CODE
INNER JOIN STOCK_LOCATIONS
ON ORDER_DATA.STOCK = STOCK_LOCATIONS.sku
INNER JOIN LOCATION_DATA
ON STOCK_LOCATIONS.location = LOCATION_DATA.location
WHERE ORDER_DATA.ORDER_REF = '21254'
GROUP BY ORDER_DATA.STOCK
ORDER BY LOCATION_DATA.pick_order ASC
这是一些示例数据
以及所需输出的示例
STOCK_LOCATIONS
sku location
123456 A1
123457 A2
123459 C1
123456 B1
123457 B2
LOCATION_DATA
location pick
A1 Y
A2 Y
B1 N
B2 N
C1 N
STOCK_DATA
STOCK_CODE PHYSICAL
123456 10
123457 0
123459 100
ORDER_DATA
ENTRY STOCK ORDER_QTY
1 123456 10
2 123457 2
3 123459 1
RETURN DATA
STOCK_CODE ENTRY LOCATION PICK ORDER_QTY PHYSICAL
123456 1 A1 Y 10 10
123457 2 A2 Y 2 0
123459 3 C1 N 1 100
这是一个更新的尝试，它会引发与未知表相关的错误：
// OPTION 1
SELECT
STOCK_LOCATIONS.*,
LOCATION_DATA.*,
STOCK_DATA.PHYSICAL,
ORDER_DATA.ENTRY,
ORDER_DATA.STOCK,
ORDER_DATA.ORDER_QTY,
(SELECT
COUNT(STOCK_LOCATIONS.location)
FROM STOCK_LOCATIONS
WHERE ORDER_DATA.STOCK = STOCK_LOCATIONS.sku
GROUP BY STOCK_LOCATIONS.sku
HAVING COUNT(STOCK_LOCATIONS.sku) > 1
) AS RowCount,
(SELECT
CASE
WHEN dat1.pick IS NOT NULL THEN loc1.location
ELSE loc2.location
END
) AS location
FROM ORDER_DATA
INNER JOIN STOCK_DATA
ON ORDER_DATA.STOCK = STOCK_DATA.STOCK_CODE
LEFT JOIN STOCK_LOCATIONS loc1
ON ORDER_DATA.STOCK = loc1.sku
LEFT JOIN LOCATION_DATA dat1
ON loc1.location = dat1.location
AND dat1.pick = 'Y'
LEFT JOIN STOCK_LOCATIONS loc2
ON ORDER_DATA.STOCK = loc2.sku
LEFT JOIN STOCK_LOCATIONS dat2
ON loc2.location = dat2.location
AND dat1.pick = 'N'
WHERE ORDER_DATA.ORDER_REF = '".$_GET_q."'
GROUP BY ORDER_DATA.STOCK
ORDER BY LOCATION_DATA.pick_order ASC
// OPTION 2
SELECT
STOCK_LOCATIONS.*,
LOCATION_DATA.*,
STOCK_DATA.PHYSICAL,
ORDER_DATA.ENTRY,
ORDER_DATA.STOCK,
ORDER_DATA.ORDER_QTY,
(SELECT
COUNT(STOCK_LOCATIONS.location)
FROM STOCK_LOCATIONS
WHERE ORDER_DATA.STOCK = STOCK_LOCATIONS.sku
GROUP BY STOCK_LOCATIONS.sku
HAVING COUNT(STOCK_LOCATIONS.sku) > 1
) AS RowCount
FROM ORDER_DATA
INNER JOIN STOCK_DATA
ON ORDER_DATA.STOCK = STOCK_DATA.STOCK_CODE
JOIN STOCK_LOCATIONS loc1
ON ORDER_DATA.STOCK = loc1.sku
JOIN LOCATION_DATA dat1
ON loc1.location = dat1.location
AND dat1.pick = CASE WHEN EXISTS
(SELECT
*
FROM STOCK_LOCATIONS loc2
JOIN LOCATION_DATA dat2
ON loc2.location = dat2.location
AND dat1.pick = 'Y'
WHERE ORDER_DATA.STOCK = loc2.sku
)
THEN 'Y' ELSE 'N' END
WHERE ORDER_DATA.ORDER_REF = '".$_GET_q."'
GROUP BY ORDER_DATA.STOCK
ORDER BY LOCATION_DATA.pick_order ASC
// OPTION 3
SELECT
STOCK_LOCATIONS.*,
LOCATION_DATA.*,
STOCK_DATA.PHYSICAL,
ORDER_DATA.ENTRY,
ORDER_DATA.STOCK,
ORDER_DATA.ORDER_QTY,
(SELECT
COUNT(STOCK_LOCATIONS.location)
FROM STOCK_LOCATIONS
WHERE ORDER_DATA.STOCK = STOCK_LOCATIONS.sku
GROUP BY STOCK_LOCATIONS.sku
HAVING COUNT(STOCK_LOCATIONS.sku) > 1
) AS RowCount,
(SELECT
STOCK_LOCATIONS.location
FROM STOCK_LOCATIONS
INNER JOIN LOCATION_DATA
ON STOCK_LOCATIONS.location = LOCATION_DATA.location
WHERE ORDER_DATA.STOCK = STOCK_LOCATIONS.sku
ORDER BY pick DESC, rand()
LIMIT 1
) AS location
FROM ORDER_DATA
INNER JOIN STOCK_DATA
ON ORDER_DATA.STOCK = STOCK_DATA.STOCK_CODE
INNER JOIN STOCK_LOCATIONS
ON ORDER_DATA.STOCK = STOCK_LOCATIONS.sku
INNER JOIN LOCATION_DATA
ON STOCK_LOCATIONS.location = LOCATION_DATA.location
WHERE ORDER_DATA.ORDER_REF = '".$_GET_q."'
GROUP BY ORDER_DATA.STOCK
ORDER BY LOCATION_DATA.pick_order ASC