SQL使用DISTINCT与INNER JOIN

Question

我现在有9列加入了使用INNER JOIN ，但我现在想从作为CIFnumber塔1移除重复。

如果我在查询顶部使用DISTINCT它不起作用。

我该怎么办？

select distinct 
    c.CIFNumber,c.FirstName,c.Surname,c.FamilyID,a.AccountID, 
    b.V‌​aluationAmount,d.NAM‌​E,ad.ID_Number,f.PrP‌​lanner 
from 
    CUSTOMERINFORMATIONFILETBL c 
inner join ACCOUNTTBL a on c.CIFNumber=a.CIFNumber 
inner join BALANCETBL b on a.AccountID=b.AccountID 
inner join FAMILYTBL f on c.FamilyID= f.FamilyID 
inner join DIVISION d on f.DIVISION=d.ID 
inner join ADDRESSTBL ad on c.CIFNumber=ad.CIF 
where 
    b.ValuationDate = '2017-09-30' and 
    d.name = 'Wealth Management' and 
    (
     ad.ID_Number= '' or 
     ad.ID_Number is null or 
     LEN(ad.ID_Number) < 13 
    ) 

Answer 1

DISTINCT函数 - 它删除特定SELECT语句中列集的重复项。如果DISTINCT没有删除列集中特定列的重复项，则意味着您在其他列中具有唯一值。

如果您只需要来自特定列的唯一值并且不关心其他列值，则可以使用窗口函数。

select * 
    from (
    select c.CIFNumber,c.FirstName,..., 
    row_number() over (partition by c.CIFNumber order by [some logic]) as rn 
    from...) as a 
    where rn = 1 

Answer 2

在至少一列中有两个或更多不同的值。如果你没有的一些数据护理可以使用TOP 1 WITH TIES + ROW_NUMBER：

select top 1 with ties 
      c.CIFNumber, 
      c.FirstName, 
      c.Surname, 
      c.FamilyID, 
      a.AccountID, 
      b.V‌​aluationAmount, 
      d.NAM‌​E, 
      ad.ID_Number, 
      f.PrP‌​lanner 
from 
    CUSTOMERINFORMATIONFILETBL c 
inner join ACCOUNTTBL a on c.CIFNumber=a.CIFNumber 
inner join BALANCETBL b on a.AccountID=b.AccountID 
inner join FAMILYTBL f on c.FamilyID= f.FamilyID 
inner join DIVISION d on f.DIVISION=d.ID 
inner join ADDRESSTBL ad on c.CIFNumber=ad.CIF 
where 
    b.ValuationDate = '2017-09-30' and 
    d.name = 'Wealth Management' and 
    (
     ad.ID_Number= '' or 
     ad.ID_Number is null or 
     LEN(ad.ID_Number) < 13 
    ) 
ORDER BY ROW_NUMBER() OVER (PARTITION BY c.CIFNumber, c.FirstName, c.Surname, c.FamilyID ORDER BY (SELECT NULL)) 

在我的例子我希望c.CIFNumber, c.FirstName, c.Surname, c.FamilyID是唯一的。