我更喜欢CTE从sql server表中删除重复的行

强烈推荐阅读本文::http://codaffection.com/sql-server-article/delete-duplicate-rows-in-sql-server/

保持原创性

WITH CTE AS
(
SELECT *,ROW_NUMBER() OVER (PARTITION BY col1,col2,col3 ORDER BY col1,col2,col3) AS RN
FROM MyTable
)

DELETE FROM CTE WHERE RN<>1

不保留原创

WITH CTE AS
(SELECT *,R=RANK() OVER (ORDER BY col1,col2,col3)
FROM MyTable)
 
DELETE CTE
WHERE R IN (SELECT R FROM CTE GROUP BY R HAVING COUNT(*)>1)

请参见下面的删除方式。

Declare @table table
(col1 varchar(10),col2 int,col3 int, col4 int, col5 int, col6 int, col7 int)
Insert into @table values 
('john',1,1,1,1,1,1),
('john',1,1,1,1,1,1),
('sally',2,2,2,2,2,2),
('sally',2,2,2,2,2,2)

创建一个名为@table的样例表，并用给定的数据加载它。

Delete  aliasName from (
Select  *,
        ROW_NUMBER() over (Partition by col1,col2,col3,col4,col5,col6,col7 order by col1) as rowNumber
From    @table) aliasName 
Where   rowNumber > 1

Select * from @table

注意:如果您按部分给出分区中的所有列，那么按顺序没有多大意义。

我知道，这个问题是三年前问的，我的答案是蒂姆发布的另一个版本，但发布只是为了对任何人有帮助。

DECLARE @TB TABLE(NAME VARCHAR(100));
INSERT INTO @TB VALUES ('Red'),('Red'),('Green'),('Blue'),('White'),('White')
--**Delete by Rank**
;WITH CTE AS(SELECT NAME,DENSE_RANK() OVER (PARTITION BY NAME ORDER BY NEWID()) ID FROM @TB)
DELETE FROM CTE WHERE ID>1
SELECT NAME FROM @TB;
--**Delete by Row Number** 
;WITH CTE AS(SELECT NAME,ROW_NUMBER() OVER (PARTITION BY NAME ORDER BY NAME) ID FROM @TB)
DELETE FROM CTE WHERE ID>1;
SELECT NAME FROM @TB;

哦，哇，我觉得准备这些答案太愚蠢了，他们就像专家的答案，包括所有的CTE和临时表等。

为了让它工作，我所做的只是使用MAX聚合ID列。

DELETE FROM table WHERE col1 IN (
    SELECT MAX(id) FROM table GROUP BY id HAVING ( COUNT(col1) > 1 )
)

注意:您可能需要多次运行它来删除重复，因为这一次只会删除一组重复的行。

with myCTE
as

(
select productName,ROW_NUMBER() over(PARTITION BY productName order by slno) as Duplicate from productDetails
)
Delete from myCTE where Duplicate>1

不使用CTE和ROW_NUMBER()，您可以通过使用group by和MAX函数删除记录，这里是一个例子

DELETE
FROM MyDuplicateTable
WHERE ID NOT IN
(
SELECT MAX(ID)
FROM MyDuplicateTable
GROUP BY DuplicateColumn1, DuplicateColumn2, DuplicateColumn3)