select
    h.IDTYPE,h.CNT,m.CNT2 
from
    HZ h
full outer join
    (select IDTYPE,count(*) as CNT2 from MX group by IDTYPE) 
on
    h.IDTYPE=m.IDTYPE and isnull(h.CNT,0)<>isnull(m.CNT2,0)

------解决方案--------------------
select A.IDTYPE , A.CNT, isnull(B.CNT2,0) as CNT2  
from HZ A
left  join
(select IDTYPE ,count(*) as CNT2
from MX
group by IDTYPE) B
on A.IDTYPE=B.IDTYPE and A.CNT<>isnull(B.CNT2,0)

------解决方案--------------------
select A.IDTYPE , A.CNT, isnull(B.CNT2,0) as CNT2 
from HZ A  
left  join  
(select IDTYPE ,count(*) as CNT2  
from MX  
group by IDTYPE) B  
on A.IDTYPE=B.IDTYPE and A.CNT < >isnull(B.CNT2,0)