Update one of 2 duplicates in an sql server database table

Question

I have got a table that got a column with duplicate values. I would like to update one of a 2 duplicate values so for example row1 = tom and row2 = tom

Answer 1

If we have this condition:

SELECT Column1 FROM Clients ORDER BY Column1

Column1
**********
Jhon
Jhon
Mike
Mike
Mike
Robert

This will work even if Column1 was duplicated n times, it will append the row number to every duplicate row except the first, try this:

BEGIN 

;WITH CTE AS 
(
    SELECT 
        ROW_NUMBER() OVER (PARTITION BY Column1 ORDER BY Column1) AS ROWNUMBER,
        Column1
    FROM Clients
)

UPDATE CTE 
SET Column1 = CONCAT(Column1, ' ', (ROWNUMBER - 1))
WHERE ROWNUMBER > 1

SELECT Column1 FROM Clients ORDER BY Column1

END 

Result:

Column1
***********
Jhon
Jhon 1
Mike
Mike 1
Mike 2
Robert

Answer 2

I had to put the with inside a from since my sql developer didnt like updating a with Copying from the answer from Nithesh

it ended up looking like this:

UPDATE Clients 
SET Column1 = 'a'
WHERE ColumnID IN (select ColumnID from 
 (  
 SELECT
       row_number() OVER(PARTITION BY Column1  ORDER BY Column1 ) AS rno,
       ColumnID FROM Clients
 )
                   where rno=2   
                  )

Answer 3

I have found this solution:

My table devices already have data and the "serial" column should be unique. The "id" is a primary key. A random 6 digits value is concatenated after the original value.

UPDATE devices 
SET serial=CONCAT(serial,'_',LPAD(FLOOR(RAND() * 999999.99), 6, '0'))    
    where id in 
    (select * FROM( 
        SELECT d1.id as id 
        FROM devices as d1, devices as d2 
        WHERE d1.id <> d2.id and d1.serial=d2.serial) as subdevices
    )

Answer 4

try this

with test as 
(
   select ROW_NUMBER() over (order by salary)rr, salary , emp_no 
   from salary
)update test set emp_no=10007 where emp_no='10002'  and rr=3

Answer 5

update wmwhse1.sku
set descr= concat (descr,'.')
where exists
(select SKU,count (DESCR)
from wmwhse1.sku
group by descr
having (count (DESCR)>1))

all sku description is updating when I run this script.

output: only 1 row should be affected