select distinct usda_lot, worksheet, lot_number, hot_wt, cwt
from lonestar_cattle a where
(usda_lot, cwt, regrade, hot_wt, class_code, classification) not in
(select usda_lot, cwt, regrade, hot_wt, class_code, classification 
from lonestar_cattle_erin)
order by 1,2,3;

select distinct usda_lot, worksheet, lot_number, hot_wt, cwt
from lonestar_cattle a where
(usda_lot, cwt, hot_wt, class_code, classification) not in
(select usda_lot, cwt, hot_wt, class_code, classification      
from lonestar_cattle_erin)
order by 1,2,3;

select distinct usda_lot, worksheet, lot_number, hot_wt
from lonestar_cattle a 
where kill_date = '2012-08-24'
and
(usda_lot, cwt, hot_wt, class_code, classification) not in
(select usda_lot, cwt, hot_wt, class_code, classification      
from lonestar_cattle_july
where kill_date = '2012-08-24')
order by 1,2,3;