Question

我有以下SQL选择。如何将其转换为删除语句，以便保留其中一行但删除重复？

select s.ForsNr, t.* 
from [testDeleteDublicates] s
join (
    select ForsNr, period,  count(*) as qty
    from [testDeleteDublicates]
    group by ForsNr, period 
    having count(*) > 1
) t on s.ForsNr = t.ForsNr and s.Period = t.Period

Answer 1

尝试使用以下内容：

方法1：

DELETE FROM Mytable WHERE RowID NOT IN (SELECT MIN(RowID) FROM Mytable GROUP BY Col1,Col2,Col3)

方法2：

;WITH cte
     AS (SELECT ROW_NUMBER() OVER (PARTITION BY ForsNr, period 
                                       ORDER BY ( SELECT 0)) RN
         FROM   testDeleteDublicates)
DELETE FROM cte
WHERE  RN > 1

希望这有帮助！

注意： 请更改表格＆amp;列名称根据您的需要！

Answer 2

只要您有一个生成的主键列（这是一个好主意），这很容易。您只需选择每个重复组的min（id）并删除其他所有内容 - 请注意，我已删除了having子句，以便从重复中排除非重复行的ID。

delete from [testDeleteDublicates]
where id not in (
    select Min(Id) as Id
    from [testDeleteDublicates]
    group by ForsNr, period 
)

如果你没有人工主键，你可能必须使用行号来达到同样的效果，因为它们的实现因供应商而异。

Answer 3

您可以使用2选项。

Add primary-key and delete accordingly

http://www.mssqltips.com/sqlservertip/1103/delete-duplicate-rows-with-no-primary-key-on-a-sql-server-table/

＆＃39; 2。将row_number（）与分区选项一起使用，运行时向每行添加行，然后删除重复的行。

Removing duplicates using partition by SQL Server

--give group by field in partition.
;with cte(
    select ROW_NUMBER() over( order by ForsNr, period partition ForsNr, period) RowNo , * from [testDeleteDublicates]
    group by ForsNr, period 
    having count(*) > 1
)

select RowNo from cte 
group by ForsNr, period

删除重复项但保留1与多列键

3 个答案: