DENSE_RANK() without duplication

Question

Here\'s what my data looks like:

| col1 | col2 | denserank | whatiwant |
|------|------|-----------|-----------|
| 1    | 1    | 1         | 1         |
| 2          


        

Answer 1

I would do it with a recursive cte like this:

declare @Dept table (col1 integer, col2 integer)

insert into @Dept values(1, 1),(2, 1),(3, 2),(4, 2),(5, 1),(6, 2),(7, 2),(8, 3)

;with a as (
select col1, col2, 
ROW_NUMBER() over (order by col1) as rn
from @Dept),
s as 
(select col1, col2, rn, 1 as dr from a where rn=1
union all
select a.col1, a.col2, a.rn, case when a.col2=s.col2 then s.dr else s.dr+1 end as dr 
from a inner join s on a.rn=s.rn+1)
col1, col2, dr from s

result:

col1        col2        dr
----------- ----------- -----------
1           1           1
2           1           1
3           2           2
4           2           2
5           1           3
6           2           4
7           2           4
8           3           5

The ROW_NUMBER is only required in case your col1 values are not sequential. If they are you can use the recursive cte straight away