SQL HELP

The following sql statement won't compile... cannot identify A1, A2, A3, A4,
A5 in the order by clause... What am i missing?

C/exec sql
C+ DECLARE R2CSR CURSOR FOR
C+
C+ SELECT MPMRS, CLSUPR, ROUND(AVG(NULLIF(A1,0)),0) AS A1,
C+ ROUND(AVG(NULLIF(A2,0)),0) AS A2, ROUND(AVG(NULLIF(A3,0)),0) AS A3,
C+ ROUND(AVG(NULLIF(A4,0)),0) As A4, ROUND(AVG(NULLIF(A5,0)),0) AS A5
C+
C+ From (SELECT MPMRS, CLSUPR, MPDATE, ROUND(AVG(NULLIF(MPOVSA,0)),0)
C+ AS A1, ROUND(AVG(NULLIF(MPI5TMS,0)),0) AS A2,
C+ ROUND(AVG(NULLIF(MP#ATTS,0)),0) AS A3,
C+ ROUND(AVG(NULLIF(MP#INSTS,0)),0) As A4,
C+ ROUND(AVG(NULLIF(MP#SCPS,0)),0) AS A5
C+
C+ FROM MRSSTATSPF JOIN CSRCLVLPF ON MPMRS = CLCSR AND MPPGRP = CLLGRP
C+
C+ WHERE MPDATE >= :YYYYMMDD3 AND
C+ MPDATE <= :YYYYMMDD AND MPPGRP = :WKGROUP AND
C+ MPDETL = 'D' AND (NOT ( MPCLVL = 4 AND MPRVIA = ' ') ) AND (NOT (
C+ MPCLVL = 5 AND MPRVIA = ' ') ) AND CLTITC >= 10 AND CLTITC <= 30
C+ AND CLTERMDATE IS NULL Group By mpMrs,CLSUPR,MPDATE) As avgList
C+
C+ Group By mpMrs,CLSUPR
C+ ORDER BY
C+ (Case When :WKSTARDSC = 'OVERALL AVERAGE' Then A1
C+ When :WKSTARDSC = 'i5 SCREEN TIME' Then A2
C+ When :WKSTARDSC = '# OF ACCOUNTS ATTEMPTED' Then A3
C+ When :WKSTARDSC = '# OF TOTAL INSTRUMENTS' Then A4
C+ When :WKSTARDSC = '# OF SCREENS COMPLETED' Then A5 End) DESC
C/end-exec




Thanks,

Jay Vaughn
Senior I5 Programmer/Analyst
RateWatch
(P) 251.209.8968
www.rate-watch.com