我需要组合2个可能有或没有数据的表，但是我需要一个完整的外连接，其中最后一个表（如果有内容，其中IsActive = 1）显示数据，而不是组合前2个表。
目前有这个：
( SELECT qp.ItemName AS name
, qp.TimeAdded AS created
, '' AS effective
, qp.VendorName AS supplier
, qp.Source AS source
, qp.VendorType AS type
, qp.Price AS cost
, '' AS price
, '' AS markup
, '' AS customer
, '' AS customerListID
, qp.VendorListID AS vendorListID
, '' AS itemListID
FROM wp_quantum_purchases AS qp
WHERE qp.IsActive = 1 AND
NOT EXISTS ( SELECT 1
FROM wp_hunter_quote_parts AS hqp
WHERE qp.ItemName = hqp.ItemName AND
hqp.IsActive = 1 ))
UNION ALL
( SELECT qs.ItemName AS name
, qs.TimeAdded AS created
, qs.SalesDate AS effective
, '' AS supplier
, qs.Source AS source
, '' AS type
, '' AS cost
, qs.Price AS price
, '' AS markup
, qs.CustomerName AS customer
, qs.CustomerListID AS customerListID
, '' AS vendorListID
, '' AS itemListID
FROM wp_quantum_sales AS qs
WHERE qs.IsActive = 1 AND
NOT EXISTS ( SELECT 1
FROM wp_hunter_quote_parts AS hqp
WHERE qs.ItemName = hqp.ItemName AND
hqp.IsActive = 1 ))
UNION ALL
( SELECT hqp.ItemName AS name
, hq.Quote_Date AS created
, hqp.SalesDate AS effective
, hqp.VendorName AS supplier
, hqp.Source AS source
, hqp.VendorType AS type
, hqp.Cost AS cost
, hqp.Price AS price
, CAST(( ( ( CAST(hqp.Price AS DECIMAL(10, 2)) - CAST(hqp.Cost AS DECIMAL(10, 2)) ) / CAST(hqp.Cost AS DECIMAL(10, 2)) ) * 100 ) AS DECIMAL(10, 2)) AS markup
, IFNULL(hq.Customer_FullName, 'N/A') AS customer
, hq.Customer_ListID AS customerListID
, hqp.VendorListID AS vendorListID
, hqp.Item_ListID AS itemListID
FROM wp_hunter_quote_parts AS hqp
LEFT JOIN wp_hunter_quotes AS hq
ON ( hq.id = hqp.QuoteID )
WHERE hqp.IsActive = 1)
ORDER BY NAME ASC;
但这是复制第1和第2表中的数据并显示数据两次。我需要将第1个和第2个表中的数据合并为1（如果存在），但要优先考虑此处的最后一个表（wp_hunter_quote_parts）作为要显示的内容，如果IsActive = 1存在于最后一张桌子（wp_hunter_quote_parts）。但是，如果IsActive = 1 wp_hunter_quote_parts中ItemName不存在wp_quantum_purchases，那么wp_quantum_sales和LEFT JOIN就好像它是1行一样。
无法执行wp_quantum_purchases，因为数据可能存在于wp_quantum_sales中，但不存在于wp_quantum_sales中，或wp_quantum_purchases中的数据可能存在于wp_hunter_quote_parts中，而wp_hunter_quote_parts中不存在数据OR数据不能存在于其中任何一个中，并且仅存在于wp_quantum_purchases中，并且wp_hunter_quote_parts中甚至可能不存在数据。
所以，基本上，如果ItemName存在于wp_quantum_purchases且IsActive = 1并且wp_hunter_quote_parts表中没有ItemName，则从hunter_quote_parts获取购买数据，否则如果ItemName存在于wp_quantum_sales中1}}从wp_hunter_quote_parts获取数据。
如果wp_quantum_sales中存在ItemName且IsActive = 1并且wp_hunter_quote_parts表中没有ItemName，则从hunter_quote_parts获取销售数据，否则(SELECT IFNULL(qp.ItemName, qs.ItemName) AS name, IFNULL(qp.TimeAdded, qs.TimeAdded) AS created, qs.SalesDate AS effective, qp.VendorName AS supplier, qp.Source AS source, qp.VendorType AS type, qp.Price AS cost, qs.Price AS price, CAST((((CAST(qs.Price AS DECIMAL(10,2)) - CAST(qp.Price AS DECIMAL(10,2))) / CAST(qp.Price AS DECIMAL(10,2))) * 100) AS DECIMAL(10,2)) AS markup, qs.CustomerName AS customer, qs.CustomerListID AS customerListID, qp.VendorListID AS vendorListID, '' AS itemListID
FROM wp_quantum_purchases AS qp, wp_quantum_sales AS qs
WHERE (qp.IsActive = 1 OR qs.IsActive = 1)
AND NOT EXISTS (
SELECT 1
FROM wp_hunter_quote_parts AS hqp
WHERE (qp.ItemName = hqp.ItemName || qs.ItemName = hqp.ItemName) AND hqp.IsActive = 1
)
)
UNION ALL
(SELECT hqp.ItemName AS name, hq.Quote_Date AS created, hqp.SalesDate AS effective, hqp.VendorName AS supplier, hqp.Source AS source, hqp.VendorType AS type, hqp.Cost AS cost, hqp.Price AS price, CAST((((CAST(hqp.Price AS DECIMAL(10,2)) - CAST(hqp.Cost AS DECIMAL(10,2))) / CAST(hqp.Cost AS DECIMAL(10,2))) * 100) AS DECIMAL(10,2)) AS markup, IFNULL(hq.Customer_FullName, 'N/A') AS customer, hq.Customer_ListID AS customerListID, hqp.VendorListID AS vendorListID, hqp.Item_ListID AS itemListID
FROM wp_hunter_quote_parts AS hqp
LEFT JOIN wp_hunter_quotes AS hq ON (hq.id = hqp.QuoteID)
WHERE (hqp.IsActive = 1))
ORDER BY name ASC
中存在ItemName来自-std=c++11的数据。
如何将第一个和第二个表组合在一起，而不是将外连接与另一个表组合？
另一个尝试：
operator()认为这个可以工作，但似乎它只是继续前进和前进，并且似乎没有完成查询。没有我能看到的错误，但是没有完成......而且这些表非常小，这很奇怪......
答案 0 :(得分：0)
我可能无法完全理解您的问题，但您可以创建前两个表的视图，然后使用第三个表进行外连接。