Re: inconsistent automatic casting between psql and function

From: Bruce Momjian <bruce(at)momjian(dot)us>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Richard Huxton <dev(at)archonet(dot)com>, Stefano Buliani <stefano(at)covestor(dot)com>, pgsql-sql(at)postgresql(dot)org
Subject: Re: inconsistent automatic casting between psql and function
Date: 2008-12-10 13:33:29
Message-ID: 200812101333.mBADXT924998@momjian.us
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Tom Lane wrote:
> Richard Huxton <dev(at)archonet(dot)com> writes:
> > That's because a quoted literal isn't necessarily a timestamp. Without
> > context it could be anything, and in the context of comparing to a date
> > the planner probably tries to make it a date.
>
> I think the real point here is this:
>
> regression=# select '2008-12-09 02:00:00'::date;
> date
> ------------
> 2008-12-09
> (1 row)
>
> ie, when it does decide that a literal should be a date, it will happily
> throw away any additional time-of-day fields that might be in there.
> Had it raised an error, Stefano might have figured out his mistake
> sooner.
>
> ISTM we deliberately chose this behavior awhile back, but I wonder
> whether it does more harm than good.

Well, it seems fine to me because it works just like the cast of a float
to an integer:

test=> select 1.23432::integer;
int4
------
1
(1 row)

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

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