在微软支持网站上有一篇关于删除重复文件的好文章。这是相当保守的——他们让你在不同的步骤中做所有的事情——但它应该适用于大的表格。

在过去，我使用了自连接来实现这一点，尽管它可能会用一个HAVING子句来美化:

DELETE dupes
FROM MyTable dupes, MyTable fullTable
WHERE dupes.dupField = fullTable.dupField 
AND dupes.secondDupField = fullTable.secondDupField 
AND dupes.uniqueField > fullTable.uniqueField

alter table MyTable add sno int identity(1,1)
    delete from MyTable where sno in
    (
    select sno from (
    select *,
    RANK() OVER ( PARTITION BY RowID,Col3 ORDER BY sno DESC )rank
    From MyTable
    )T
    where rank>1
    )

    alter table MyTable 
    drop  column sno

另一种表达方式:——

DELETE A
FROM   TABLE A,
       TABLE B
WHERE  A.COL1 = B.COL1
       AND A.COL2 = B.COL2
       AND A.UNIQUEFIELD > B.UNIQUEFIELD 

我想这会很有帮助。这里，ROW_NUMBER() OVER(分区由res1。Title ORDER BY res1.Id)作为num来区分重复的行。

delete FROM
(SELECT res1.*,ROW_NUMBER() OVER(PARTITION BY res1.Title ORDER BY res1.Id)as num
 FROM 
(select * from [dbo].[tbl_countries])as res1
)as res2
WHERE res2.num > 1

使用这个

WITH tblTemp as
(
SELECT ROW_NUMBER() Over(PARTITION BY Name,Department ORDER BY Name)
   As RowNumber,* FROM <table_name>
)
DELETE FROM tblTemp where RowNumber >1

创建具有相同结构的新空白表 像这样执行查询 插入tc_category1 SELECT * 从tc_category GROUP BY category_id, application_id count(*) > 然后执行这个查询 插入tc_category1 SELECT * 从tc_category GROUP BY category_id, application_id count(*) = 1