这是实际场景当中的一个例子，拿出来分析总结思路。

-- SQL 查询 --
SELECT  orderQuery.Rk_SkuCode ,
        orderQuery.SkuName,
        SUM(ISNULL(orderQuery.OrderTotal, 0))
        - SUM(ISNULL(removeQuery.RemoveTotal, 0))
        - SUM(ISNULL(pickQuery.PickTotal, 0))
        - SUM(ISNULL(tempPickQuery.TempPickTotal, 0)) AS RealOrders ,
        SUM(ISNULL(orderQuery.OrderTotal, 0)) AS Orders ,
        SUM(ISNULL(removeQuery.RemoveTotal, 0)) AS Removes ,
        SUM(ISNULL(pickQuery.PickTotal, 0)) AS Picks ,
        SUM(ISNULL(stockQuery.StockTotal, 0)) AS Stocks ,
        SUM(ISNULL(tempPickQuery.TempPickTotal, 0)) AS TempPicks
FROM    ( SELECT    Rk_SkuCode , do.Rk_SkuName AS SkuName,
                    SUM(do.UnitQty) AS OrderTotal
          FROM      dbo.SALE_Bill_Sale_Order o ,
                    dbo.SALE_Bill_Sale_Order_Detail do
          WHERE     o.Fk_ATS_Wfs_NodeId != 100100170
                    AND o.Fk_BillTypeId = 100100010
                    AND o.Pk_OrderId = do.Fk_OrderId
                    AND o.Fk_WarehouseId = 140416154556733
          GROUP BY  Rk_SkuCode,do.Rk_SkuName
        ) orderQuery
        LEFT OUTER JOIN ( SELECT    Rk_SkuCode ,
                                    SUM(rd.Quantity) AS RemoveTotal
                          FROM      dbo.WMS_Bill_Remove r ,
                                    dbo.WMS_Bill_Remove_Detail rd
                          WHERE     r.Pk_RemoveId = rd.Fk_RemoveId
                                    AND r.Fk_WarehouseId = 140416154556733
                                    AND r.Fk_BillTypeId = 100100110
                                    AND r.Fk_ATS_Wfs_NodeId = 100300140
                          GROUP BY  Rk_SkuCode
                        ) removeQuery ON orderQuery.Rk_SkuCode = removeQuery.Rk_SkuCode
        LEFT OUTER JOIN ( SELECT    Rk_SkuCode ,
                                    SUM(s.Quantity) AS PickTotal
                          FROM      dbo.WMS_Stock s ,
                                    dbo.WMS_Info_PartArea p
                          WHERE     p.Pk_PartAreaId = s.Fk_PartAreaId
                                    AND s.Fk_WarehouseId = 140416154556733
                                    AND p.Ek_Type = 100100120
                          GROUP BY  Rk_SkuCode
                        ) pickQuery ON orderQuery.Rk_SkuCode = pickQuery.Rk_SkuCode
        LEFT OUTER JOIN ( SELECT    Rk_SkuCode ,
                                    SUM(s.Quantity) AS StockTotal
                          FROM      dbo.WMS_Stock s ,
                                    dbo.WMS_Info_PartArea p
                          WHERE     p.Pk_PartAreaId = s.Fk_PartAreaId
                                    AND s.Fk_WarehouseId = 140416154556733
                                    AND p.Ek_Type = 100100150
                          GROUP BY  Rk_SkuCode
                        ) stockQuery ON orderQuery.Rk_SkuCode = stockQuery.Rk_SkuCode
        LEFT OUTER JOIN ( SELECT    Rk_SkuCode ,
                                    SUM(s.Quantity) AS TempPickTotal
                          FROM      dbo.WMS_Stock s
                          WHERE     s.Fk_WarehouseId = 140416154556733
                                    AND s.Fk_LocationId = 140612114677165
                          GROUP BY  Rk_SkuCode
                        ) tempPickQuery ON orderQuery.Rk_SkuCode = tempPickQuery.Rk_SkuCode
GROUP BY orderQuery.Rk_SkuCode,orderQuery.SkuName
HAVING  ( SUM(ISNULL(orderQuery.OrderTotal, 0))
          - SUM(ISNULL(removeQuery.RemoveTotal, 0))
          - SUM(ISNULL(pickQuery.PickTotal, 0))
          - SUM(ISNULL(tempPickQuery.TempPickTotal, 0)) ) > 0