有沒有更好的方式來寫這個選擇查詢

SELECT t1.X, 
     t1.Item_Code, 
     t2.X, 
     t2.Item_Code 
FROM (SELECT Sum(e.item_qty) AS X, 
       A.Item_Code 
     FROM [Item Master]A 
       INNER JOIN [Counter Issue Details] e 
         ON e.Item_Code = A.Item_Code 
       INNER JOIN [Counter Master] CM 
         ON CM.Counter_Code = e.Counter_Code 
     WHERE e.Item_Code = A.Item_Code 
       AND A.Type_Code = 0 
     GROUP BY A.Item_Code)t1, 
     (SELECT Sum(e.item_qty) AS X, 
       A.Item_Code 
     FROM [Item Master]A 
       INNER JOIN [Counter Return Details] e 
         ON e.Item_Code = A.Item_Code 
       INNER JOIN [Counter Master] CM 
         ON CM.Counter_Code = e.Counter_Code 
     WHERE e.Item_Code = A.Item_Code 
       AND A.Type_Code = 0 
     GROUP BY A.Item_Code)t2

蔭得到OUTPT已有沒有更好的方式來寫這個選擇查詢

X          Item_Code        Y          Item_Code 
--------------------------------------- --------------------------------------- --------------------------------------- --------------------------------------- 
3998.000        1          2.00         11 
2000.000        2          2.00         11 
2000.000        3          2.00         11 
2504.000        4          2.00         11 
2384.000        5          2.00         11 
2456.000        6          2.00         11 
2372.000        7          2.00         11 
4900.000        9          2.00         11 
2000.000        10          2.00         11 
3948.000        11          2.00         11

現在我正在重複記錄的商品代碼11 2的所有10條記錄。我希望將Y值映射到物品代碼11本身，其他所有物品都應該爲零

來源

2016-04-27 Venkatvasan

請使用t1和t2之間的連接 –

你想完成什麼？我可能會建議你問另一個問題（這個問題已經有答案），並解釋你在做什麼，提供樣本數據和期望的結果。 –

您的問題是舊式笛卡爾連接充當CROSS JOIN。如果您考慮正確加入，您不會將數據翻倍;

SELECT t1.Item_Code 
    ,t1.X t1_x 
    ,ISNULL(t2.X,0) t2_x 
FROM (
    SELECT SUM(e.item_qty) AS X 
     ,A.Item_Code 
    FROM [Item Master] A 
    INNER JOIN [Counter Issue Details] e ON e.Item_Code = A.Item_Code 
    INNER JOIN [Counter Master] CM ON CM.Counter_Code = e.Counter_Code 
    WHERE e.Item_Code = A.Item_Code 
     AND A.Type_Code = 0 
    GROUP BY A.Item_Code 
    ) t1 

LEFT JOIN 
    (
     SELECT SUM(e.item_qty) AS X 
      ,A.Item_Code 
     FROM [Item Master] A 
     INNER JOIN [Counter Return Details] e ON e.Item_Code = A.Item_Code 
     INNER JOIN [Counter Master] CM ON CM.Counter_Code = e.Counter_Code 
     WHERE e.Item_Code = A.Item_Code 
      AND A.Type_Code = 0 
     GROUP BY A.Item_Code 
     ) t2 
ON t1.Item_Code = t2.Item_Code

這將返回t1中的所有值和t2中的匹配信息。編輯：t2.X現在將顯示0，沒有數據而不是按要求填充NULL。

在這個問題上有一些很好的資源;

Which join syntax is better?

http://sqlblog.com/blogs/aaron_bertrand/archive/2009/10/08/bad-habits-to-kick-using-old-style-joins.aspx

來源

2016-04-27 11:19:46

非常感謝Mr.Benner，它的工作原理非常完美。如果沒有我想要顯示的數據，請保存我的日子 – Venkatvasan

，而不是顯示NULL。如何獲取此.. – Venkatvasan

將選擇更改爲'ISNULL（t2.X， 0）t2_x'。我編輯了我的原始代碼以向您展示該示例。 –

你有沒有加入你們派生表T1和T2之間的規定。如果您期望t1的結果，則需要使用LEFT JOIN，而不是每行都使用t2。

SELECT t1.X 
     , t1.Item_Code 
     , t2.X 
     , t2.Item_Code 
FROM (SELECT SUM(e.item_qty) AS X 
        , A.Item_Code 
      FROM  [Item Master] A 
        INNER JOIN [Counter Issue Details] e ON e.Item_Code = A.Item_Code 
        INNER JOIN [Counter Master] CM ON CM.Counter_Code = e.Counter_Code 
      WHERE  e.Item_Code = A.Item_Code 
        AND A.Type_Code = 0 
      GROUP BY A.Item_Code 
     ) t1 
     LEFT JOIN (SELECT SUM(e.item_qty) AS X 
          , A.Item_Code 
        FROM [Item Master] A 
          INNER JOIN [Counter Return Details] e ON e.Item_Code = A.Item_Code 
          INNER JOIN [Counter Master] CM ON CM.Counter_Code = e.Counter_Code 
        WHERE e.Item_Code = A.Item_Code 
          AND A.Type_Code = 0 
        GROUP BY A.Item_Code 
       ) t2 ON t1.Item_Code = t2.Item_Code;

來源

2016-04-27 11:22:22

有沒有更好的方式來寫這個選擇查詢

回答

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