Re: Date calculation produces wrong output with 7.02

Mark Stosberg (mark(at)summersault(dot)com) writes:

> [PostgreSQL 7.0.2 on i686-pc-linux-gnu, compiled by gcc 2.96]
> cascade=> select date(CURRENT_DATE + ('30 days'::reltime));
> date
> ----------
> 9097-10-20

Ugh. What is happening here is that there is no '+' operator between
types date and reltime, but there is one between date and int4 (with
behavior of adding that many days to the date). And reltime is
considered binary-compatible with int4, so you get

select date(CURRENT_DATE + ('30 days'::reltime)::int4);

Now '30 days'::reltime::int4 yields 2592000, so you get a silly final
result.

The correct query for Mark is

select date(CURRENT_DATE + ('30 days'::interval));

but I wonder whether the binary equivalence between reltime and int4
might not be ill-advised. Thomas, any thoughts here?

regards, tom lane