Case Statement in BODS

Hi,

Am trying to implement the below case login in bods for a column

CASE

WHENcds.DevStatusReasonIDisNULLTHENNULL

WHENcds.DevStatusOtherReasonISNULLTHENRTRIM(RTRIM(Reason.DevStatusReason))

ELSERTRIM(LTRIM(Reason.DevStatusReason))+' - '+RTRIM(LTRIM(cds.DevStatusOtherReason))

ENDNAReason

I tried using IFTHENELSE but getting errors.

Can some one get the syntax for above stmt in bods