帮忙看看这条SQL语句哪里不对

SELECT 单号=B.sd_id
  ,来源站点=(select station_name FROM dbo.db_station_total WHERE station_id=A.station_id_xs)
  ,拣货站点=(select station_name FROM dbo.db_station_total WHERE station_id=B.station_id_aim)
  ,主订单录单时间=MAX(A.input_date)
  ,主订单审核时间=MAX(A.verify_date)
  ,从订单审核时间=MAX(B.verify_date)
  ,计划用时=MAX(DATEDIFF(second,A.verify_date,B.verify_date)/3600.00)
  ,拣货用时=MAX(DATEDIFF(second,B.verify_date,C.verify_date)/3600.00)
  ,待发 = MAX(c.df_hour)
 FROM (
SELECT dbo.pre_sd.sd_id,ItemExclusiveCode,station_id_xs,verify_date,input_date 
FROM dbo.pre_sd,dbo.pre_sd_item 
WHERE is_hypotaxis='0' AND pre_sd.sd_id=dbo.pre_sd_item.sd_id) AS A, 
(SELECT dbo.pre_sd.sd_id, source_item_id,station_id_aim,verify_date,ItemExclusiveCode 
FROM dbo.pre_sd,dbo.pre_sd_item 
WHERE is_hypotaxis='1' AND pre_sd.sd_id=dbo.pre_sd_item.sd_id) AS B,
(SELECT  dbo.tj_dm_ck.verify_date,  
dbo.db_fb_track.fb_id,
station_id_location,
station_id_transfer,   
        dbo.tj_dm_ck_item.source_item_id,
        df_hour = DATEDIFF(second,
                               CASE WHEN db_fb_track.sh_date > db_fb_track.verify_date
                                         AND db_fb_track.sh_date < db_fb_track.fh_date
                                    THEN db_fb_track.sh_date
                                    ELSE db_fb_track.verify_date
                               END,
                               CASE WHEN db_fb_track.fh_date > db_fb_track.verify_date
                                    THEN db_fb_track.fh_date
                                    ELSE GETDATE()
                               END) / 3600.00
FROM    
        db_fb_track,
        dbo.db_fb_item,
        dbo.tj_dm_ck_item,
        dbo.tj_dm_ck
WHERE   db_fb_item.fb_id = db_fb_track.fb_id  
  AND dbo.tj_dm_ck.dm_id=dbo.tj_dm_ck_item.dm_id 
  AND dbo.db_fb_item.source_item_id=dbo.tj_dm_ck_item.ItemExclusiveCode   
  AND dbo.tj_dm_ck.station_id=dbo.db_fb_track.station_id_location    
          AND ISNULL(db_fb_track.is_destroy, '0') = '0'  )AS C
WHERE A.ItemExclusiveCode=B.source_item_id AND B.ItemExclusiveCode=C.source_item_id 
AND A.input_date >'2012-12-01' 
GROUP BY B.sd_id,station_id_xs,station_id_aim