/* SQL script */ 
create table table1 (f1 int,f2 char( 10 ),f3 numeric( 6 , 2 ))
create table table2 (f1 int,f2 char( 10 ),f3 numeric( 6 , 2 ))
go
insert table1 (f1,f2,f3) values( 1 ,'line1', 1 . 00 )
insert table1 (f1,f2,f3) values( 2 ,'line2', 2 . 00 )
insert table1 (f1,f2,f3) values( 3 ,'line3', 3 . 00 )
insert table1 (f1,f2,f3) values( 4 ,'line4', 4 . 00 )
go
insert table2 (f1,f2,f3) values( 1 ,'line1', 1 . 01 )
insert table2 (f1,f2,f3) values( 2 ,'line2', 2 . 00 )
insert table2 (f1,f2,f3) values( 3 ,'line3', 3 . 00 )
insert table2 (f1,f2,f3) values( 4 ,'line4', 4 . 01 )
go
select * into #table3 from  table1
union all
select * from table2
go
select count(*) as cnt,f1,f2,f3 
from #table3
group by f1,f2,f3
having count(*)= 1 
go

 /* results */ 
cnt         f1          f2         f3       
 ----------- ----------- ---------- -------- 
 
 1 . 00          1 . 00         line1       1 . 00 
 1 . 00          1 . 00         line1       1 . 01 
 1 . 00          4 . 00         line4       4 . 00 
 1 . 00          4 . 00         line4       4 . 01 

( 4  row(s) affected)