Sum not working

Question

In region definition have a SQL Query (Updateable Report) from a collection. Everything is working great even the radio buttons. I want to sum the regular hours column so under the report attributes tab, I checked the sum box for the REG_HOURS column, but it will not sum. Just shows zero all the time.
select
x.APPR_STATUS,
CASE WHEN NVL(x.APPR_STATUS,'1') = '1' THEN 'CHECKED ' ELSE '' END CHECKED_Y,
CASE WHEN NVL(x.APPR_STATUS,'2') = '2' THEN 'CHECKED ' ELSE '' END CHECKED_N,
CASE WHEN x.APPR_STATUS > 0 AND x.UPLOAD_ID > 0 THEN 'DISABLED ' ELSE '' END DISABLE_RADIO,
x.ID,
x.LINEITEM_DATE,
x.ATT_CODE,
x.LABOR_CATEGORY,
x.CC,
x.WO,
x.DESCRIPTION,
x.SQUAWK,
x.REG_HOURS,
x.COMMENTS,
x.BADGE,
x.PAY_CODE,
x.CHARGE_TYPE,
x.LAST_EDITED_BY,
x.APPR_STATUS APPR_STATUS_HIDDEN,
x.APPROVER,
x.UPLOAD_ID UPLOAD_ID_HIDDEN,
x.APPR_STATUS_SAVE,
decode(x.EDIT_FLAG, 'N', ' ',
'<a href="'
     || 'f?p=&APP_ID.:23:&SESSION.::&DEBUG.::'
     || 'P23_SELECTED_ID:'
     ||  ID
     || ">'
|| '<img src="#IMAGE_PREFIX#menu/pencil2_16x16.gif"></a>') Edit,
x.ID AS COPY,
decode(x.EDIT_FLAG, 'Y',
-- decode(x.last_edited_by, :A_USER_BADGE,
'<a href="'
    ||'f?p=&APP_ID.:23:&SESSION.::&DEBUG.::'
    ||'P23_DELETE_ID:'
    || ID
    ||">'
||'<img src="#IMAGE_PREFIX#delete.gif"></a>',
' ') DEL,
'#ROWNUM#' ITEM_NUMBER
from ( select ac.c003 ID,
ac.c004 LINEITEM_DATE,
ac.c005 ATT_CODE,
ac.c006 LABOR_CATEGORY,
ac.c007 CC,
ac.c008 WO,
ac.c009 DESCRIPTION,
ac.c010 SQUAWK,
ac.c011 REG_HOURS,
ac.c012 COMMENTS,
ac.c013 BADGE,
ac.c014 PAY_CODE,
ac.c015 CHARGE_TYPE,
ac.c016 LAST_EDITED_BY,
ac.c017 APPR_STATUS,
ac.c018 APPROVER,
ac.c019 UPLOAD_ID,
ac.c020 APPR_STATUS_SAVE,
ac.c021 EDIT_FLAG
from apex_collections ac
where ac.collection_name='APPRTIMECOLLECTION') x

Answer 1

Peter,
Thanks for responding. Since you did respond I am going to give you credit. Thank you. I did resolve my problem yesterday.
ANSWER:
When working with collections, everything is treated as a character unless you specify otherwise. So I changed the reg_hours field from ac.c011 to ac.n001 and the sum is working now.
select
x.APPR_STATUS,
CASE WHEN NVL(x.APPR_STATUS,'1') = '1' THEN 'CHECKED ' ELSE '' END CHECKED_Y,
CASE WHEN NVL(x.APPR_STATUS,'2') = '2' THEN 'CHECKED ' ELSE '' END CHECKED_N,
CASE WHEN x.APPR_STATUS > 0 AND x.UPLOAD_ID > 0 THEN 'DISABLED ' ELSE '' END DISABLE_RADIO,
x.ID,
x.LINEITEM_DATE,
x.ATT_CODE,
x.LABOR_CATEGORY,
x.CC,
x.WO,
x.DESCRIPTION,
x.SQUAWK,
x.REG_HOURS,
x.COMMENTS,
x.BADGE,
x.PAY_CODE,
x.CHARGE_TYPE,
x.LAST_EDITED_BY,
x.APPR_STATUS APPR_STATUS_HIDDEN,
x.APPROVER,
x.UPLOAD_ID UPLOAD_ID_HIDDEN,
x.APPR_STATUS_SAVE,
decode(x.EDIT_FLAG, 'N', ' ',
'<a href="'
     || 'f?p=&APP_ID.:23:&SESSION.::&DEBUG.::'
     || 'P23_SELECTED_ID:'
     ||  ID
     || ">'
|| '<img src="#IMAGE_PREFIX#menu/pencil2_16x16.gif"></a>') Edit,
x.ID AS COPY,
decode(x.EDIT_FLAG, 'Y',
-- decode(x.last_edited_by, :A_USER_BADGE,
'<a href="'
    ||'f?p=&APP_ID.:23:&SESSION.::&DEBUG.::'
    ||'P23_DELETE_ID:'
    || ID
    ||">'
||'<img src="#IMAGE_PREFIX#delete.gif"></a>',
' ') DEL,
'#ROWNUM#' ITEM_NUMBER
from ( select ac.c003 ID,
ac.c004 LINEITEM_DATE,
ac.c005 ATT_CODE,
ac.c006 LABOR_CATEGORY,
ac.c007 CC,
ac.c008 WO,
ac.c009 DESCRIPTION,
ac.c010 SQUAWK,
ac.n001     REG_HOURS,
ac.c012 COMMENTS,
ac.c013 BADGE,
ac.c014 PAY_CODE,
ac.c015 CHARGE_TYPE,
ac.c016 LAST_EDITED_BY,
ac.c017 APPR_STATUS,
ac.c018 APPROVER,
ac.c019 UPLOAD_ID,
ac.c020 APPR_STATUS_SAVE,
ac.c021 EDIT_FLAG
from apex_collections ac
where ac.collection_name='APPRTIMECOLLECTION') x