How below column transform into double column with ascending group(sql)

Question

I try to get this in single query but failed. Do we need to use group set?

colA
200
400
300
500
200

transform into

colA	colB
200	1
300	2
300	2
400	3
500	4

Answer 1

Maybe use DENSE_RANK() windowing function if available in your SQL database

like

select ColA, 
DENSE_RANK() OVER( order by ColA) as colB
from yourtable