選擇單記錄多個類似的結果

Question

SELECT  TOP (100) PERCENT dbo.vwLatestEquipment.equipServID, dbo.tblEquipInvoice.invoiceDateSent, dbo.tblEquipment.equipManafacturer, 
        dbo.tblEquipInvoice.contractNumber, dbo.tblEquipment.equipmentID, dbo.tblEquipment.equipStatus, dbo.tbl_work_locations.work_location, 
        dbo.vwLatestEquipment.calibDueDate 
FROM   dbo.vwLatestEquipment INNER JOIN 
        dbo.tblEquipLocations ON dbo.vwLatestEquipment.locationID = dbo.tblEquipLocations.locationID INNER JOIN 
        dbo.tblEquipInvoice ON dbo.tblEquipLocations.invoiceID = dbo.tblEquipInvoice.invoiceID INNER JOIN 
        dbo.tblEquipment ON dbo.vwLatestEquipment.equipServID = dbo.tblEquipment.equipServID INNER JOIN 
        dbo.tbl_work_locations ON dbo.tblEquipInvoice.workLocationID = dbo.tbl_work_locations.work_id 
GROUP BY dbo.tbl_work_locations.work_location, dbo.vwLatestEquipment.equipServID, dbo.tblEquipInvoice.invoiceDateSent, dbo.tblEquipment.equipManafacturer, 
        dbo.tblEquipInvoice.contractNumber, dbo.tblEquipment.equipmentID,  dbo.tblEquipment.equipStatus, dbo.tbl_work_locations.work_location, 
        dbo.vwLatestEquipment.calibDueDate 
ORDER BY dbo.vwLatestEquipment.equipServID 

這是一個一直傳遞到我從我的繼任者，認爲上述工作正常進行的目的，除了它返回calibDateDue所有值我想要equipmentID的每一個項目是爲它返回每個設備（equipmentID）的最新calibDueDate任何幫助將不勝感激今天，因爲我煎炸，無法取得很大進展。

Answer 1

我想讓它爲設備（equipmentID）的每個項目 返回最新的calibDueDate。

由於您使用的是TOP (100) PERCENT，我將假定您使用的是SQL Server。然後你可以使用排序功能：

ROW_NUMBER() OVER(PARTITION BY equipmentID 
        ORDER BY calibDueDate DESC) 

然後與排名只選擇行= 1，像這樣：

;WITH CTE 
AS 
(
    SELECT 
     dbo.vwLatestEquipment.equipServID, 
     dbo.tblEquipInvoice.invoiceDateSent, 
     dbo.tblEquipment.equipManafacturer, 
     dbo.tblEquipInvoice.contractNumber, 
     dbo.tblEquipment.equipmentID, 
     dbo.tblEquipment.equipStatus, 
     dbo.tbl_work_locations.work_location, 
     dbo.vwLatestEquipment.calibDueDate, 
     ROW_NUMBER() OVER(PARTITION BY equipmentID 
         ORDER BY calibDueDate DESC) row_num 
    FROM dbo.vwLatestEquipment 
    INNER JOIN dbo.tblEquipLocations 
      ON dbo.vwLatestEquipment.locationID=dbo.tblEquipLocations.locationID 
    INNER JOIN dbo.tblEquipInvoice 
      ON dbo.tblEquipLocations.invoiceID=dbo.tblEquipInvoice.invoiceID 
    INNER JOIN dbo.tblEquipment 
      ON dbo.vwLatestEquipment.equipServID=dbo.tblEquipment.equipServID 
    INNER JOIN dbo.tbl_work_locations 
      ON dbo.tblEquipInvoice.workLocationID=dbo.tbl_work_locations.work_id 
) 
SELECT TOP (100) PERCENT * 
FROM CTE 
WHERE row_num = 1 
ORDER BY equipServID;