Select into with Case

Is this statement valid:

Exec SQL
Select Coalesce(Sum(RHQYRC),0),
Case CWTCD
When ItmIsCwt Then Coalesce(Sum(RHCOST*RHWRTC),0)
Else Coalesce(Sum(RHCOST*RHQYRC),0)
End
Into :VQYRC,
:VCOST
From DMRECHST
Where RHITEM = :ITNBR and
RHDTRC >= :WkBegDat and
RHDTRC <= :WkEndDat;

The RPG compiler is yelling at me saying "SQL0206: Position 26 Column or
global variable CWTCD not found."

Variable CWTCD is a field in a file in the program that is NOT being
processed via SQL.

Thanks.