select usercode from table1 where usercode not exists (select Usercode from table2) select t1.usercode from table1 t1,table2 t2 where t1.usercode<>t2.usercode
select usercode from table1 minus select Usercode from table2
select a.usercode from table1 a,table2 b where a.usercode<>b.usercode
select t1.usercode from table1 t1,table2 t2 where t1.usercode<>t2.usercode
select usercode from table1 minus (select Usercode from table2)
select usercode from t1 where not exists (select 'X' from t2 where t1.usercode=t2.usercode)
minus
select Usercode from table2
a.usercode<>b.usercode