如何從SQL Server中的表中刪除重複的記錄？

Question

如何從SQL Server中刪除表中的重複記錄？

Answer 1

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 2

以下問題和給出的答案有可能是你

Remove Duplicate Records

可以選擇分和ROWID的最大最好的幫助（如果有和標識字段，否則增加一個）

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 3

要刪除行的組合col_1, col_2, ... col_n重複的行，可以使用公用表表達式;

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; 

由於行是通過列出列的內容進行分類，如果行是在各方面是相同的，你仍然需要列出查詢中的所有列。

與往常一樣，在運行之前進行測試和/或備份，從因特網上的隨機人員中刪除生產數據。

Answer 4

添加標識列到表：

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

然後從表中刪除記錄運行以下查詢：

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;