SQL>
SQL> declare
2 v_start_ts TIMESTAMP:= to_timestamp('14:00:00','HH24:MI:SS');
3 v_end_ts TIMESTAMP:= to_timestamp('15:12:24','HH24:MI:SS');
4 v_delta_int INTERVAL DAY TO SECOND;
5 begin
6 v_delta_int:=v_end_ts-v_start_ts;
7 DBMS_OUTPUT.put_line(v_delta_int);
8 end;
9 /
+00 01:12:24.000000
PL/SQL procedure successfully completed.
SQL>