過濾SQL查詢返回的結果

Question

我一直在努力整個下午工作 - 這似乎很簡單，但我必須錯過一些東西！

我有一個查詢返回一些數據，它返回的兩列是「PackageWeight」和「PackageGroup」。從本質上講，我想過濾掉這些數據，以便每個「PackageGroup」只顯示一行 - 應該是「PackageWeight」列中值最高的那一行。

看起來很簡單，但我不能讓它在SQL Server中使用TOP 1和GROUP BY的組合工作。我肯定錯過了什麼！

SELECT VendorID, PackageID, PackageWeight, PackageGroup 
    FROM (SELECT VendorID, COUNT(*) AS qty 
      FROM VendorServices 
     GROUP BY VendorID 
     ) cs 
    JOIN (SELECT PackageServices.PackageID, lookupPackages.PackageWeight, lookupPackages.PackageGroup, COUNT(*) AS qty 
      FROM PackageServices 
      JOIN lookupPackages ON PackageServices.PackageID = lookupPackages.PackageID 
      GROUP BY PackageServices.PackageID, lookupPackages.PackageWeight, lookupPackages.PackageGroup 
     ) ps ON cs.qty >= ps.qty 
    WHERE (SELECT COUNT(*) 
      FROM VendorServices cs2 
      JOIN PackageServices ps2 ON cs2.ServiceTypeID = ps2.ServiceID 
     WHERE cs2.VendorID = cs.VendorID 
      AND ps2.PackageID = ps.PackageID 
     ) = ps.qty 

此查詢返回完整的數據集，我需要過濾。然而我的努力迄今未能:(

任何幫助非常讚賞

編輯 - 由於下面的貢獻者，到目前爲止，我有以下查詢：

with result_cte as 
(
SELECT VendorID, PackageID, PackageWeight, PackageGroup, 
    RANK() over (partition by PackageGroup order by PackageWeight desc) as [rank] 
FROM (SELECT VendorID, COUNT(*) AS qty 
    FROM VendorServices 
    GROUP BY VendorID 
    ) cs 
JOIN (SELECT PackageServices.PackageID, lookupPackages.PackageWeight, lookupPackages.PackageGroup, COUNT(*) AS qty 
    FROM PackageServices 
    JOIN lookupPackages ON PackageServices.PackageID = lookupPackages.PackageID 
    GROUP BY PackageServices.PackageID, lookupPackages.PackageWeight, lookupPackages.PackageGroup 
    ) ps ON cs.qty >= ps.qty 
WHERE (SELECT COUNT(*) 
    FROM VendorServices cs2 
    JOIN PackageServices ps2 ON cs2.ServiceTypeID = ps2.ServiceID 
    WHERE cs2.VendorID = cs.VendorID 
    AND ps2.PackageID = ps.PackageID 
    ) = ps.qty 
) 

select * 
from result_cte 
WHERE [rank] = 1 
ORDER BY VendorID 

到目前爲止，好，我仍然會看看@gbn提出的APPLY運算符，因爲這對我來說是新的 - 我仍然需要做一些測試來確保這個查詢在100％的時間內運行，但最初的跡象是好的！

感謝迄今爲止所做的貢獻。

編輯2 - 遺憾的是，在用更多示例數據填充數據庫後，此查詢失敗。它似乎錯過了一些條目。

也許我需要更多地解釋一下這裏發生了什麼。通過我的原始查詢返回的數據會列出系統中的每個客戶，以及派生的PackageID（由該查詢計算）以及在查找表中分配給該Package的權重和組。

我需要過濾原始結果表，這樣我才能從每個組中獲取不超過一個包，每個客戶（每個客戶可能有一個或多個組的包，但可能沒有每個組的包）

明天我會帶着更新的一面看，因爲我想我可能會在'看不到樹木的情況'！

謝謝大家。

Answer 1

你可以試試嗎？如果在同一組中有多個具有相同權重的記錄，那麼這並非無懈可擊。還有其他方法來處理它。

with result_cte as 
(
SELECT VendorID, PackageID, PackageWeight, PackageGroup 
FROM (SELECT VendorID, COUNT(*) AS qty 
    FROM VendorServices 
    GROUP BY VendorID 
    ) cs 
JOIN (SELECT PackageServices.PackageID, lookupPackages.PackageWeight, lookupPackages.PackageGroup, COUNT(*) AS qty 
    FROM PackageServices 
    JOIN lookupPackages ON PackageServices.PackageID = lookupPackages.PackageID 
    GROUP BY PackageServices.PackageID, lookupPackages.PackageWeight, lookupPackages.PackageGroup 
    ) ps ON cs.qty >= ps.qty 
WHERE (SELECT COUNT(*) 
    FROM VendorServices cs2 
    JOIN PackageServices ps2 ON cs2.ServiceTypeID = ps2.ServiceID 
    WHERE cs2.VendorID = cs.VendorID 
    AND ps2.PackageID = ps.PackageID 
    ) = ps.qty 
) 

select * 
from result_cte 
where result_cte.PackageWeight = (select top 1 highestweight.PackageWeight from result_cte highestweight 
           where highestweight.PackageGroup = result_cte.PackageGroup 
           order by highestweight.PackageWeight desc) 

或者，你可以這樣做：

with result_cte as 
(
SELECT VendorID, PackageID, PackageWeight, PackageGroup, 
    ROW_NUMBER() over (partition by PackageGroup order by PackageWeight desc) as [row] 
FROM (SELECT VendorID, COUNT(*) AS qty 
    FROM VendorServices 
    GROUP BY VendorID 
    ) cs 
JOIN (SELECT PackageServices.PackageID, lookupPackages.PackageWeight, lookupPackages.PackageGroup, COUNT(*) AS qty 
    FROM PackageServices 
    JOIN lookupPackages ON PackageServices.PackageID = lookupPackages.PackageID 
    GROUP BY PackageServices.PackageID, lookupPackages.PackageWeight, lookupPackages.PackageGroup 
    ) ps ON cs.qty >= ps.qty 
WHERE (SELECT COUNT(*) 
    FROM VendorServices cs2 
    JOIN PackageServices ps2 ON cs2.ServiceTypeID = ps2.ServiceID 
    WHERE cs2.VendorID = cs.VendorID 
    AND ps2.PackageID = ps.PackageID 
    ) = ps.qty 
) 

select * 
from result_cte 
where [row] = 1 

Answer 2

你願意接受一個任意的供應商和PackageID如果多個包有一組相同的最大重量？如果正常，只是把聚集在他們身上還有PackageWeight：

SELECT max(VendorID), max(PackageID), max(PackageWeight), PackageGroup 
... 
GROUP BY PackageGroup 

否則，你需要做的E.Y.建議並執行嵌套查詢以首先查找每個組的最大權重並自行處理重複項（如果有）。

Answer 3

您可以使用MAX功能：

SELECT * FROM #one 
lbs groups 
5 0 
4 0 
1 0 
9 1 
2 1  

SELECT groups,MAX(lbs) 
FROM #one 
GROUP BY groups 

groups (No column name) 
0 5 
1 9 

Answer 4

由於後由Eric.K.Yung - 我終於解決了這個用了他的問題，但「通過分區」部分添加廠商ID（有效客戶ID）到的查詢。這確保了爲所有客戶返回包裹。

感謝所有人的貢獻。最終的查詢是：

with result_cte as 
(
SELECT VendorID, PackageID, PackageWeight, PackageGroup, 
    ROW_NUMBER() over (partition by PackageGroup, VendorID order by PackageWeight desc) as [row] 
FROM (SELECT VendorID, COUNT(*) AS qty 
    FROM VendorServices 
    GROUP BY VendorID 
    ) cs 
JOIN (SELECT PackageServices.PackageID, lookupPackages.PackageWeight, lookupPackages.PackageGroup, COUNT(*) AS qty 
    FROM PackageServices 
    JOIN lookupPackages ON PackageServices.PackageID = lookupPackages.PackageID 
    GROUP BY PackageServices.PackageID, lookupPackages.PackageWeight, lookupPackages.PackageGroup 
    ) ps ON cs.qty >= ps.qty 
WHERE (SELECT COUNT(*) 
    FROM VendorServices cs2 
    JOIN PackageServices ps2 ON cs2.ServiceTypeID = ps2.ServiceID 
    WHERE cs2.VendorID = cs.VendorID 
    AND ps2.PackageID = ps.PackageID 
    ) = ps.qty 
) 

select * 
from result_cte 
where [row] = 1