SUM与多个表MySQL

Question

问题是谁使桌子不是我。这个问题基于数据库适配。所以，我需要你们的帮助。

我有表需要SUM的Quantity的项目。

我用这个代码来获得从items到orderset_details表的Quantaties。

SELECT 
    I.ItemId, I.Code, I.Item, I.Minimum, I.Maximum, 
    IFNULL 
    (
     (
      SELECT SUM(ROUND(h.Quantity)) 
      FROM orderset_details AS H 
      WHERE H.ItemId = I.ItemId 
     ) 
     , 0 
    ) as 'Balance' 
FROM items AS I 
GROUP BY I.ItemId 

输出

但也有需要是负数量表。我的代码在一次只能获得1项的所有数量。

SELECT 
    sts.TransferDate as 'Transaction Date' 
    , sts.TransNumber as 'Document Number' 
    , orderset_details.Quantity as 'Quantity' 
    , '' as 'Po Number' 
    , '' as 'Sales Invoice' 
    , orderset_details.Cost as 'Cost' 
    , orderset_details.SerialNumber as 'Serial Number' 
    , orderset_details.LotNumber as 'Lot Number' 
    , location.Location as 'Location' 
FROM sts 
LEFT JOIN orderset_details ON sts.OrdersetId = orderset_details.OrdersetId 
LEFT JOIN location ON location.LocationId = sts.LocationIdTo 
WHERE orderset_details.ItemId = '4786' 
UNION 
SELECT 
     drs.OrderDate 
    , drs.TransNumber 
    , orderset_details.Quantity 
    , drs.PONumber 
    , '' 
    , orderset_details.Cost 
    , orderset_details.SerialNumber 
    , orderset_details.LotNumber 
    , suppliers.Supplier 
FROM drs 
LEFT JOIN orderset_details ON drs.OrdersetId = orderset_details.OrdersetId 
LEFT JOIN suppliers ON suppliers.SupplierId = drs.SupplierId 
WHERE orderset_details.ItemId = '4786' 
UNION 
SELECT 
     stockadjustment.TransactionDate 
    , stockadjustment.TransactionId 
    , IF(reason.AddsToStock = '1', orderset_details.Quantity, 0 - orderset_details.Quantity) 
    , '' 
    , '' 
    , orderset_details.Cost 
    , orderset_details.SerialNumber 
    , orderset_details.LotNumber 
    , location.Location 
FROM stockadjustment 
LEFT JOIN reason ON reason.ReasonId = stockadjustment.ReasonId 
LEFT JOIN orderset_details ON stockadjustment.OrdersetId = orderset_details.OrdersetId 
LEFT JOIN location ON location.LocationId = stockadjustment.LocationId 
WHERE orderset_details.ItemId = '4786' 
UNION 
SELECT 
     issueslip.OrderDate 
    , issueslip.TransNumber 
    , IF(issueslip.OrdersetId = orderset_details.OrdersetId, 0 - orderset_details.Quantity, -1 * orderset_details.Quantity) 
    , '' 
    , '' 
    , orderset_details.Cost 
    , orderset_details.SerialNumber 
    , orderset_details.LotNumber 
    , customers.Customer  
FROM issueslip 
LEFT JOIN orderset_details ON issueslip.OrdersetId = orderset_details.OrdersetId 
LEFT JOIN customers ON customers.CustomerId = issueslip.CustomerId 
WHERE orderset_details.ItemId = '4786' 
UNION 
SELECT 
     invoice.OrderDate 
    , invoice.TransNumber 
    , IF(invoice.OrdersetId = orderset_details.OrdersetId, 0 - orderset_details.Quantity, -1 * orderset_details.Quantity) 
    , '' 
    , '' 
    , orderset_details.Cost 
    , orderset_details.SerialNumber 
    , orderset_details.LotNumber 
    , customers.Customer 
FROM invoice 
LEFT JOIN orderset_details ON invoice.OrdersetId = orderset_details.OrdersetId 
LEFT JOIN customers ON customers.CustomerId = invoice.CustomerId 
WHERE orderset_details.ItemId = '4786' 

我只是从这个代码需要的是为Negative Quantity ConditionLIKEIF(reason.AddsToStock = '1', orderset_details.Quantity, 0 - orderset_details.Quantity)和2等多个查询。

如何将这些查询结合到我的第一条查询上？

Answer 1

你可以做这样的事情：

SELECT I.ItemId, I.Code, I.Item, I.Minimum, I.Maximum, 
      COALESCE(SUM(ROUND(
       CASE SA.ReasonId WHEN R.ReasonId 
        THEN h.Quantity 
        ELSE -h.Quantity 
       END)), 0) as 'Balance' 
FROM  items AS I 
CROSS JOIN reason AS R 
LEFT JOIN orderset_details AS H 
     ON H.ItemId = I.ItemId 
LEFT JOIN stockadjustment AS SA 
     ON SA.OrdersetId = H.OrdersetId 
WHERE  R.AddsToStock = '1' 
GROUP BY I.ItemId