NOT IN oprator issue Oracle
===

Here is my query:
    Select a.* from Table1 a, Table2 b
    Where 
    a.tid=b.tid and 
    b.createddate=(Select max(createddate) from Table2) and
    a.tid not in (Select distinct tid from Table3);

The problem is I know this should return some valid output but it does not. The issue us with the last line in the **a.tid not in (Select distinct tid from Table3);** if I replace Select distinct tid from Table3 with hard coded values like ('T001','T002','T003','T004') then it works fine and returns data.

Whats wrong? Am I missing something? Please help.
