Question

I want my sql statement to use order by clause using Case Statement
and the column in used in order by is a computed column, for example:

declare @pOrderBy int
set @pOrderBy=1
Select ArtistId as Counting, ROW_NUMBER() OVER (ORDER BY  
CASE WHEN (@pOrderBy = 1) THEN "Counting" end)
from master.dbo.Album

I got the error

Invalid column name 'Counting'.

I want to mention here that in actual query my Counting column is a computed column like:

Count(*) as Counting

Answer 1

You can’t reuse the column alias at the same level as it is defined.

In this case I would just use ORDER BY ArtistId rather than trying to reuse the alias. For more complicated expressions you might consider defining it in a CTE or a CROSS APPLY as discussed in this article.