Question

如何从SQL Server中的表中删除重复记录？

Answer 1

要删除列col_1, col_2, ... col_n组合重复的行，可以使用公用表表达式;

WITH cte AS (
  SELECT *, 
         ROW_NUMBER() OVER (PARTITION BY col1, ..., col_n ORDER BY col_1) AS rn 
  FROM table_1
)
DELETE FROM cte WHERE rn<>1;

由于行按列出的列的内容进行分类，如果行在所有方面都相同，您仍需要列出查询中的所有列。

与往常一样，在生产数据上从Internet上的随机用户中删除之前进行测试和/或备份。

Answer 2

WITH CTE AS(
   SELECT [col1], [col2], [col3], [col4], [col5], [col6], [col7],
       RN = ROW_NUMBER()OVER(PARTITION BY col1 ORDER BY col1)
   FROM dbo.Table1
)
DELETE FROM CTE WHERE RN > 1

Example

Answer 3

以下问题和给出的答案对您来说可能是最好的帮助

Remove Duplicate Records

您可以选择rowId的最小值和最大值（如果有和身份字段，则另外添加一个）

DELETE MyTable 
FROM MyTable
LEFT OUTER JOIN (
   SELECT MIN(RowId) as RowId, Col1, Col2, Col3 
   FROM MyTable 
   GROUP BY Col1, Col2, Col3
) as KeepRows ON
   MyTable.RowId = KeepRows.RowId
WHERE
   KeepRows.RowId IS NULL
Use

Source

Answer 4

在表格中添加标识列：

Alter table tbl_name add Id int identity(1,1)

然后运行以下查询以从表中删除记录：

Delete from tbl_Name where Id not in(select min(Id) from tbl_Name group by RowId)

Answer 5

//duplicate_data_table contains duplicate values 

create temp as (select distinct * from duplicate_data_table);

    drop duplicate_data_table;

create duplicate_data_table as (select * from temp);

    drop temp;

如何从SQL Server中删除表中的重复记录？

5 个答案: