Question

在SQL Server中，我想对具有多个列的distinct语句中的单个列 [BLC.Container_No] 使用SELECT关键字。

我的查询：

SELECT BLD.VV_CODE,
       V.Vessel_name,
       BLD.Arrival_date,
       ISNULL(IGM.VIR_NO, 'NULL') AS VIR_NO,
       ISNULL(BLD.TERMINAL_CODE, 'NULL') AS TERMINAL_CODE,
       BLD.BL_NO,
       ISNULL(BLD.Parent_BL, 'NULL') AS Parent_BL,
       BLD.Consignee_Description,
       DO.DO_Issue_Date,
       CA.CAgent_Name,
       BLC.Container_No,
       CS.Container_Size_Description
FROM Vessel V,
     IGM,
     BL_DATA BLD,
     CAgent CA,
     Delivery_Order DO,
     BL_Container BLC,
     Container_Size CS
WHERE V.Vessel_code = SUBSTRING(BLD.VV_CODE, 1, 3)
  AND BLD.VV_CODE = IGM.VV_CODE
  AND DO.CAgent_Code = CA.CAgent_Code
  AND BLD.BL_NO = BLC.BL_NO
  AND BLC.Container_Size_Code = CS.Container_Size_Code;

Answer 1

您不能那样做。 SQL怎么知道您想要哪个BLC.Container_NO？您必须告诉sql您想要哪个。您可以使用这个。

With cte as(
SELECT BLD.VV_CODE,
       V.Vessel_name,
       BLD.Arrival_date,
       ISNULL(IGM.VIR_NO, 'NULL') AS VIR_NO,
       ISNULL(BLD.TERMINAL_CODE, 'NULL') AS TERMINAL_CODE,
       BLD.BL_NO,
       ISNULL(BLD.Parent_BL, 'NULL') AS Parent_BL,
       BLD.Consignee_Description,
       DO.DO_Issue_Date,
       CA.CAgent_Name,
       BLC.Container_No,
        ROW_NUMBER() OVER (PARTITION BY BLD.VV_CODE ORDER BY BLC.Container_No asc) AS row_num
       ,CS.Container_Size_Description
FROM Vessel V,
     IGM,
     BL_DATA BLD,
     CAgent CA,
     Delivery_Order DO,
     BL_Container BLC,
     Container_Size CS
WHERE V.Vessel_code = SUBSTRING(BLD.VV_CODE, 1, 3)
  AND BLD.VV_CODE = IGM.VV_CODE
  AND DO.CAgent_Code = CA.CAgent_Code
  AND BLD.BL_NO = BLC.BL_NO
  AND BLC.Container_Size_Code = CS.Container_Size_Code)

  SELECT *
FROM cte
WHERE rn = 1

Answer 2

您不能..除非您对列进行分组..然后您可以指定分组功能，例如count(distinct field1)或sum(distinct field2)等。

在SQL Server的Select语句中选择多个列时，如何对单个列使用distinct关键字

2 个答案: