to_timestamp

select * from opgcep2.gcal_execution_task where created_at > TO_TIMESTAMP ('28-Sep-15 7:10:10.123000', 'DD-Mon-RR HH24:MI:SS.FF')
and created_at < TO_TIMESTAMP ('28-Sep-15 7:48:10.123000', 'DD-Mon-RR HH24:MI:SS.FF') order by created_at asc;