Narendra,
> I tried all these. This is what I get
> SQL> SELECT "interval"(cast(422 as varchar) || ' seconds');
> SELECT "interval"(cast(422 as varchar) || ' seconds')
> *
> ERROR at line 1:
> ORA-00906: missing left parenthesis
> SQL> select '422 seconds'::interval;
> select '422 seconds'::interval
> *
> ERROR at line 1:
> ORA-00923: FROM keyword not found where expected
Those don't look like PostgreSQL error messages. I think you are using
some other database.
-Josh Berkus