What will be the output?
;with cte as(select rn=1 union all select rn=rn+1 from cte where rn<10)
select * from cte

This is a recursive common table expression. It will start the value of rn=1 and it in the recursive part it will keep on increment the value of rn each time to 1 till it satisfies the stopping condition. The output will be 1 to 10