select count(*) from
(
select * from m_Farmerrecedit_2010 where (farmercode like '55202%')
union all
select * from m_Farmer_2010 t
where farmercode not in(select farmercode from m_Farmerrecedit_2010 where farmercode like '55202%')
) a
(
select * from m_Farmerrecedit_2010 where (farmercode like '55202%')
union all
select * from m_Farmer_2010 t
where farmercode not in(select farmercode from m_Farmerrecedit_2010 where farmercode like '55202%')
) a
...
select * from m_Farmer_2010 t
where not exists(select 1 from m_Farmerrecedit_2010 m where farmercode like '55202%'
and m.farmercode =t.farmercode)
select count(*) from
(select * from aa
union all
select * from m_Farmer_2010 t where not exists(select null from aa where
aa.farmercode=t.farmercode)
)