T-SQL and Group By

[Goksly]

Bit confused by this and I cannot get any consistancy. Say I have a select statement that has a big case statement which I call 'x'. Sometimes I am able to say 'Group By x' and other times it says this is an unknown column and I have to copy and paste the case statement after the group by which works (but is a pain - duplication).

Does anyone know why?

 

[Goksly]

Apparently you can't use an alias (range in my example) in a WHERE or GROUP BY clause etc.

But I have in the past... which was the source of my confusion (no consistancy). By past I mean a week or so ago... on the same day a similar query wouldnt let me. Megh!

Thanks for your post.