[GENERAL] Finding missing records

[Stefano B.]

Hi,   I have two identical tables   table1 (f1,f2,f3,f4 primary key (f1,f2,f3,f4)) table2 (g1,g2,g3,g4 primary key (g1,g2,g3,g4))   How can I find the difference between the two tables? table1 has 10000 records table2 has  9900 records (these records are in table1 as well)   I'd like to find 100 missing records. I have try this query   select f1,f2,f3,f4 from table1 where (f1,f2,f3,f4) NOT IN (select f1,f2,f3,f4 from table2)   but it seems not work (as I want). It returns me no records. If I use the IN clause it returns me all 10000 table1 records.   Thanks in advance Stefano