Question

请考虑以下情况

我有一张如下表格

Tag | Id | Client | ....and more columns
c     30    X
c     40    Y
c     50    X
c     60    A
c     30    B 
c     40    C
d     50    D
d     70    E 
d     80    X
d     90    Z
i     30    X
i     90    Z
i    100    X
i     40    M

我想从表中选择记录，如果tag = i 从结果集中删除下面的行

  i     30    X
  i     90    Z

这是因为id = 90的行已经出现tag = d和client = Z. 但是行

i     40    M

即使客户端= C已经出现id = 40，也不能删除

，因为客户端列值不同。

DELETE FROM myTable
WHERE tag=i AND id IN( SELECT id FROM myTable t1
                      INNER JOIN myTable t2 
                      ON t1.id=t2.id 
                      WHERE tag=d or tag=c )

Answer 1

根据您的规则，您可以使用CTE跟WITH CTE AS ( SELECT [Tag], [Id], [Client], RN=ROW_NUMBER()OVER(PARTITION BY [Id], [Client] ORDER BY [Tag]) FROM dbo.Tags ) DELETE FROM CTE WHERE RN > 1 AND [Tag] = @Tag; TAG ID CLIENT RN i 30 X 2 i 90 Z 2来检测和删除重复项：

{{1}}

ROW_NUMBER

删除这些记录：

{{1}}

DEMO

Answer 2

这应该可以解决问题......

declare @Tag as varchar(10)
set @Tag = 'i'

  -- The select statement to view the record to be deleted
  select MyTable.Tag,MyTable.Id,MyTable.Client,RecordToDelete.totalCount from [SampleDB].dbo.[MyTable]
  inner join 
  (
    SELECT 
        [Id]
        ,[Client],
        TotalCount = count(id)
    FROM [SampleDB].dbo.[MyTable]
    group by id,Client
  ) as RecordToDelete 
  on RecordToDelete.Id=MyTable.Id and RecordToDelete.Client =MyTable.Client
  where RecordToDelete.totalCount>1 and MyTable.Tag = @Tag


  -- The delete statement
  delete [SampleDB].dbo.[MyTable]
  where MyTable.Tag = @Tag and MyTable.Id in (
      --select MyTable.Tag,MyTable.Id,MyTable.Client,RecordToDelete.totalCount from [SampleDB].dbo.[MyTable]
      select MyTable.Id from [SampleDB].dbo.[MyTable]
      inner join 
      (
        SELECT 
            [Id]
            ,[Client],
            TotalCount = count(id)
        FROM [SampleDB].dbo.[MyTable]
        group by id,Client
      ) as RecordToDelete 
      on RecordToDelete.Id=MyTable.Id and RecordToDelete.Client =MyTable.Client
      where RecordToDelete.totalCount>1 and MyTable.Tag = @Tag
  )

Answer 3

你可以试试这个：

DELETE FROM DUU
WHERE EXISTS
(
    SELECT TAG,ID,CLIENT FROM 
    (
        SELECT TAG,ID,CLIENT FROM DUU A WHERE TAG IN ('I') AND  EXISTS (
        SELECT TAG,ID,CLIENT FROM DUU B WHERE TAG IN ('C') AND A.ID=B.ID AND A.CLIENT=B.CLIENT) 
        UNION 
        SELECT TAG,ID,CLIENT FROM DUU A WHERE TAG IN ('I') AND  EXISTS (
        SELECT TAG,ID,CLIENT FROM DUU B WHERE TAG IN ('D') AND A.ID=B.ID AND A.CLIENT=B.CLIENT)
    ) C WHERE DUU.TAG=C.TAG AND DUU.ID= C.ID AND DUU.CLIENT = C.CLIENT
)

注意：DUU是表的名称。

删除重复记录SQL Server

3 个答案: