SQL>
SQL> declare
2 t1 timestamp := current_timestamp + 1 ;
3 i1 INTERVAL DAY TO SECOND;
4 begin
5 i1 := t1 - current_timestamp;
6 dbms_output.put_line(i1);
7 end;
8 /
+00 23:59:59.789000
PL/SQL procedure successfully completed.
SQL>
SQL>