ALM - Case statement

Hi all,

I am using ALM 11.5. I want to know if ALM allows CASE when. When I type in Case when it doesnt seem to recognise the Case at all. I also get the error "FROM keyword not found where expected". And also pls let me know if I'm using CASE appropriately.

SELECT AL_absolute_path,ALL_LISTS.AL_DESCRIPTION
case when ALL_LISTS.AL_absolute_path ='AAAAAPAAB' then 'A1'
when ALL_LISTS.AL_absolute_path ='AAAAAPAAD' then 'A'
when ALL_LISTS.AL_absolute_path ='AAAAAPAAI' then 'B'
when ALL_LISTS.AL_absolute_path ='AAAAAPAAK' then 'C' else ALL_LISTS.AL_absolute_path end as AL_absolute_path
FROM all_lists

Thanks

Nithya