I have a table as follows, I want to automatically increase the SIRANO value according to the rows with the same MF_ID value in this table.
| SIRANO | MF_ID | 
|---|---|
| NULL | 30 | 
| NULL | 30 | 
| NULL | 30 | 
| NULL | 31 | 
| NULL | 31 | 
| NULL | 32 | 
must be:
| SIRANO | MF_ID | 
|---|---|
| 1 | 30 | 
| 2 | 30 | 
| 3 | 30 | 
| 1 | 31 | 
| 2 | 31 | 
| 1 | 32 | 
DECLARE @counter int
SET @counter = 0
update A 
set SIRANO = (case when A.MF_ID=B.MF_ID then @counter+1
                           else 0
                           end)
FROM MYTABLE_0002 a 
INNER JOIN MYTABLE_0002 b
on a.MF_ID = b.MF_ID
 
    