Need to delete duplicate records from the table using row_number()

问题

I am having a table test having data as follows and I want to delete the trsid 124 and I have millions entry in my DB it is just a scenarion. Concept is to delete the duplicate entry from the table

--------------------------------------------
TrsId   |   ID  |   Name    |
--------------------------------------------    
123     |   1   |   ABC     |   
124     |   1   |   ABC     |

I am trying something like

delete from test
select T.* from
(
    select ROW_NUMBER() over (partition by ID order by name) as r,
           Trsid,
           ID,
           name
    from test
) t
where r = 2

Even if I update the query which is Ok for me

update test set id=NULL
select T.* from
(
    select ROW_NUMBER() over (partition by ID order by name) as r,
           Trsid,
           ID,
           name
    from test
) t
where r = 2

But if i run both this query it deletes all the records from table test. And if i update it update both the records. I dont know what I am doing wrong here

回答1:

WITH cte AS
(
    SELECT ROW_NUMBER() OVER(PARTITION by ID ORDER BY name) AS Row
    FROM test
)

DELETE FROM cte
WHERE Row > 1

回答2:

Use the below query.

      ;WITH cte_1
         AS (SELECT ROW_NUMBER() OVER(PARTITION BY ID,NAME ORDER BY TrsId ) Rno,*
               FROM YourTable)
         DELETE
         FROM cte_1
         WHERE RNO>1

回答3:

WITH cte_DUP AS (
SELECT * FROM (
select <col1,col2,col3..coln>, row_number() 
over(partition by <col1,col2,col3..coln>
order by <col1,col2,col3..coln>  ) rownumber  
from <your table> ) AB  WHERE  rownumber > 1)

DELETE FROM cte_DUP WHERE ROWNUMBER > 1

回答4:

To find duplicate records we can write like below query,

;WITH dup_val 
     AS (SELECT a, 
                b, 
                Row_number() 
                  OVER( 
                    partition BY a, b 
                    ORDER BY b, NAME)AS [RANK] 
         FROM   table_name) 
SELECT * 
FROM   dup_val 
WHERE  [rank] <> 1;

来源：https://stackoverflow.com/questions/39564777/need-to-delete-duplicate-records-from-the-table-using-row-number

标签

sql

sql-server-2008

row-number