Request for Info:
Hmmm... I see FOUR rows with the SRC being 10, so what makes assets 2000, 4000 different from the others. What is the other criteria you are expecting ?
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Just a tip for future questions - give us the data as *SQL*, ie, create table plus insert statements like I've done below
SQL> create table t ( asset int, src int, d date );
Table created.
SQL>
SQL>
SQL> insert into t values (1000,10,'01-jan-2017');
1 row created.
SQL> insert into t values (1000,11,'01-mar-2017');
1 row created.
SQL> insert into t values (1000,34,'01-feb-2017');
1 row created.
SQL> insert into t values (2000,10,'10-jan-2017');
1 row created.
SQL> insert into t values (3000,10,'10-jan-2017');
1 row created.
SQL> insert into t values (3000,11,'11-feb-2017');
1 row created.
SQL> insert into t values (4000,10,'14-feb-2017');
1 row created.
SQL> insert into t values (5000,11,'15-mar-2017');
1 row created.
SQL> insert into t values (5000,34,'20-apr-2017');
1 row created.
SQL>
SQL> select * from t t_main
2 where src = 10
3 and not exists
4 ( select * from t
5 where t.asset = t_main.asset
6 and src != 10 );
ASSET SRC D
---------- ---------- ---------
2000 10 10-JAN-17
4000 10 14-FEB-17