case statements don't seem to translate to AR

[TNichols2012]

SQL:
select
case
when column1 = 1 then 'Yes'
when column1 = 2 then 'No'
else 'Other' end as Answer
from table1 where username is not null

AR:
Table1.find_by_username is not null(username is not null)

Not sure AR will give me what I'm trying to do with SQL.