How to GROUP BY var created from Case-when statement

[devon59]

Can anyone help?
I would like to group the records by the variable I created from case when statement but I got an error saying that that new variable is not part of the table. For example, this is what I have.

Select A, B, C,
case when A=1 then 'Y' else 'N' end as Flag
from Client_table
group by Flag
Thank you

 

[PWise]

group by case when A=1 then 'Y' else 'N' end

 

[devon59]

Thank you so much pwise. That worked.