VD
simply "no".
A case construct has one "output", a bit like a macro which generates text, if the text contains no semicolons then it can be invoked many times within a base SAS statement.
The "output" of a case construct need not be a column in the output, but it cannot be more than one column, unless you assign it to a column to which you can refer more than once.
An example of where a case construct does not become a column is where that "output" is used in deriving another column as in:
select name, case when age gt 12 then 'teen' else 'pre-teen'
end !! 'ager' length=15 as life_stage , age
from sashelp.class
I expect you'll find examples more relevant to your situation
I'm not sure, but expect that a case construct could return a value you could use in a where or having clause,
Probably reading the documentation would clarify.
luck
peterC