SELECT sls.outlet  ,prefc.description,
   SUM(case when sls.docdt BETWEEN TO_DATE('01-JAN-2008','DD-MON-YYYY') AND TO_DATE('31-OCT-2008','DD-MON-YYYY')
          then slsd.amt1
          else 0 end) "2008_data",
 SUM(case when sls.docdt BETWEEN TO_DATE('01-JAN-2009','DD-MON-YYYY')
               AND TO_DATE('31-OCT-2009','DD-MON-YYYY')
          then slsd.amt1
          else 0 end) "2009_data"
  FROM sls_head sls          ,
 sls_detail slsd             ,
 prodfle pf                  ,
 prodref pref                ,
 prodref_classification prefc,
 customer c                  ,
 ctypes ct
 WHERE sls.docno=slsd.docno
AND sls.outlet    =slsd.outlet
AND sls.docdt    =slsd.docdt
AND sls.tc       =slsd.tc
AND sls.docdt BETWEEN TO_DATE('01-JAN-2008','DD-MON-YYYY') AND TO_DATE('31-OCT-2009','DD-MON-YYYY')
AND slsd.prodcd            =pf.prodcd
AND pf.refcode             =pref.refcode
AND pf.class_code          =prefc.class_code
AND c.outlet                =sls.outlet
AND c.cusno                =sls.cusno
AND c.custype              =ct.code
--AND prefc.refcode         IN ('A')
and prefc.class_code in ('AA','AB','AC')
GROUP BY sls.outlet,
prefc.description
ORDER BY 1

SELECT outlet
      ,sum(case when description in ('AA','AB','AC','AD','AE') then 2008_DATA else 0 end)
      ,sum(case when description in ('shoe','shirt','sandal' then 2008_data else 0 end)
FROM (...)