CREATE TABLE car(Id int identity(1,1), PersonId int, CarId int)

INSERT INTO car(PersonId,CarId)
VALUES(1,2),(1,3),(1,2),(2,4)

--SELECT * FROM car

;WITH CTE as(
SELECT ROW_NUMBER() over (PARTITION BY personid,carid order by personid,carid) as rn,Id,PersonID,CarId from car)

DELETE FROM car where Id in(SELECT Id FROM CTE WHERE rn>1)

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 

DELETE LU 
FROM   (SELECT *, 
               Row_number() 
                 OVER ( 
                   partition BY col1, col1, col3 
                   ORDER BY rowid DESC) [Row] 
        FROM   mytable) LU 
WHERE  [row] > 1 

下面的查询用于删除重复的行。本例中的表以ID作为标识列，具有重复数据的列是Column1、Column2和Column3。

DELETE FROM TableName
WHERE  ID NOT IN (SELECT MAX(ID)
                  FROM   TableName
                  GROUP  BY Column1,
                            Column2,
                            Column3
                  /*Even if ID is not null-able SQL Server treats MAX(ID) as potentially
                    nullable. Because of semantics of NOT IN (NULL) including the clause
                    below can simplify the plan*/
                  HAVING MAX(ID) IS NOT NULL) 

下面的脚本显示GROUP BY、HAVING、ORDER BY在一个查询中的用法，并返回带有重复列及其计数的结果。

SELECT YourColumnName,
       COUNT(*) TotalCount
FROM   YourTableName
GROUP  BY YourColumnName
HAVING COUNT(*) > 1
ORDER  BY COUNT(*) DESC 

我知道这个问题已经回答了，但我已经创建了非常有用的sp，它将为表副本创建一个动态删除语句:

    CREATE PROCEDURE sp_DeleteDuplicate @tableName varchar(100), @DebugMode int =1
AS 
BEGIN
SET NOCOUNT ON;

IF(OBJECT_ID('tempdb..#tableMatrix') is not null) DROP TABLE #tableMatrix;

SELECT ROW_NUMBER() OVER(ORDER BY name) as rn,name into #tableMatrix FROM sys.columns where [object_id] = object_id(@tableName) ORDER BY name

DECLARE @MaxRow int = (SELECT MAX(rn) from #tableMatrix)
IF(@MaxRow is null)
    RAISERROR  ('I wasn''t able to find any columns for this table!',16,1)
ELSE 
    BEGIN
DECLARE @i int =1 
DECLARE @Columns Varchar(max) ='';

WHILE (@i <= @MaxRow)
BEGIN 
    SET @Columns=@Columns+(SELECT '['+name+'],' from #tableMatrix where rn = @i)

    SET @i = @i+1;
END

---DELETE LAST comma
SET @Columns = LEFT(@Columns,LEN(@Columns)-1)

DECLARE @Sql nvarchar(max) = '
WITH cteRowsToDelte
     AS (
SELECT ROW_NUMBER() OVER (PARTITION BY '+@Columns+' ORDER BY ( SELECT 0)) as rowNumber,* FROM '+@tableName
+')

DELETE FROM cteRowsToDelte
WHERE  rowNumber > 1;
'
SET NOCOUNT OFF;
    IF(@DebugMode = 1)
       SELECT @Sql
    ELSE
       EXEC sp_executesql @Sql
    END
END

如果你创建这样的表格

IF(OBJECT_ID('MyLitleTable') is not null)
    DROP TABLE MyLitleTable 


CREATE TABLE MyLitleTable
(
    A Varchar(10),
    B money,
    C int
)
---------------------------------------------------------

    INSERT INTO MyLitleTable VALUES
    ('ABC',100,1),
    ('ABC',100,1), -- only this row should be deleted
    ('ABC',101,1),
    ('ABC',100,2),
    ('ABCD',100,1)

    -----------------------------------------------------------

     exec sp_DeleteDuplicate 'MyLitleTable',0

它将从表中删除所有重复项。如果运行它时不带第二个参数，它将返回一条SQL语句来运行。

如果您需要排除任何列，只需在调试模式下运行它，获取代码并按照您的喜好修改它。

我想提一下这种方法，它可能是有帮助的，并且适用于所有SQL服务器: 通常只有一到两个副本，副本的id和数量是已知的。在这种情况下:

SET ROWCOUNT 1 -- or set to number of rows to be deleted
delete from myTable where RowId = DuplicatedID
SET ROWCOUNT 0