雖然我在SQL Server 2008 R2中使用「Distinct」和「Group By」，但爲什麼使用內部連接但記錄重複？

Question

這是查詢時，我運行它它給了我重複的記錄，但我刪除INNER JOIN planingOrderBookHeader PLOH ON sd.StyleID=PLOH.StyleID和PLOH.OderBookID列，它給記錄沒有重複，但我需要記錄與列名PLOH.OderBookID我該如何解決這個問題？

SELECT 
     CPO.ID 
     ,CPO.StyleID 
     ,cpo.CustomerPo 
     ,PLOH.OderBookID 
     ,cpo.Process 
     ,CPD.Qty 
     ,cpd.RefID 
     ,cpd.Uom 
     ,UM.MeshType 
     ,PRC.Name 
     ,STC.NewStyleno 
     ,SD.TypeID 
     ,itm.Name Part 
     ,SD.ColorID 
     ,COL.Name Color 
     ,SD.FabricID 
     ,FAB.Name Faric 
     ,SHD.ItemID 
     ,ITD.Name Item 
     ,SHD.Image 
FROM CustomerPO_Header CPO 
    INNER JOIN styleconfirmHeader STC ON STC.StyleID=CPO.StyleID 
    INNER JOIN CustomerPo_Details CPD ON CPO.ID=CPD.CusPOHeaderID 
    INNER JOIN StyleHeader SHD ON SHD.StyleID=CPO.StyleID 
    INNER JOIN StyleDetails SD ON CPO.StyleID=SD.StyleID 
    INNER JOIN ItemDetails itm ON SD.TypeID=itm.ID 
    INNER JOIN ColorDetails COL ON SD.ColorID=COL.ID 
    INNER JOIN ItemFabricDetails FAB ON FAB.ID=SD.FabricID 
    INNER JOIN UOM UM ON Um.ID=CPD.Uom 
    INNER JOIN ItemTypeDetails ITD ON SHD.ItemID=ITD.ID 
    INNER JOIN process PRC ON PRC.ID=CPO.Process 
    INNER JOIN planingOrderBookHeader PLOH ON sd.StyleID=PLOH.StyleID 

PLZ幫我

Answer 1

很難不知道你有什麼數據來檢驗。但是，您可以嘗試將導致您的重複項的表移動到子查詢中而不是聯接中。所以像這樣：

SELECT 
    CPO.ID 
    ,CPO.StyleID 
    ,cpo.CustomerPo 
    ,(SELECT PLOH.OderBookID FROM planingOrderBookHeader PLOH WHERE sd.StyleID=PLOH.StyleID) AS OderBookID 
    ,cpo.Process 
    ,CPD.Qty 
    ,cpd.RefID 
    ,cpd.Uom 
    ,UM.MeshType 
    ,PRC.Name 
    ,STC.NewStyleno 
    ,SD.TypeID 
    ,itm.Name Part 
    ,SD.ColorID 
    ,COL.Name Color 
    ,SD.FabricID 
    ,FAB.Name Faric 
    ,SHD.ItemID 
    ,ITD.Name Item 
    ,SHD.Image 
FROM CustomerPO_Header CPO 
INNER JOIN styleconfirmHeader STC ON STC.StyleID=CPO.StyleID 
INNER JOIN CustomerPo_Details CPD ON CPO.ID=CPD.CusPOHeaderID 
INNER JOIN StyleHeader SHD ON SHD.StyleID=CPO.StyleID 
INNER JOIN StyleDetails SD ON CPO.StyleID=SD.StyleID 
INNER JOIN ItemDetails itm ON SD.TypeID=itm.ID 
INNER JOIN ColorDetails COL ON SD.ColorID=COL.ID 
INNER JOIN ItemFabricDetails FAB ON FAB.ID=SD.FabricID 
INNER JOIN UOM UM ON Um.ID=CPD.Uom 
INNER JOIN ItemTypeDetails ITD ON SHD.ItemID=ITD.ID 
INNER JOIN process PRC ON PRC.ID=CPO.Process 

當然這可能會有性能影響。