Re: Casting Varchar to Numeric

Added to TODO.detail/typeconv.

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Tom Lane wrote:
> Bruce Momjian <pgman@candle.pha.pa.us> writes:
> > I can see problems with automatically casting numeric to text because
> > you have to guess the desired format, but going from text to numeric
> > seems quite easy to do.  Is there a reason we don't do it?
>
> I do not think it's a good idea to have implicit casts between text and
> everything under the sun, because that essentially destroys the type
> checking system.  What we need (see previous discussion) is a flag in
> pg_proc that says whether a type conversion function may be invoked
> implicitly or not.  I've got no problem with offering text(numeric) and
> numeric(text) functions that are invoked by explicit function calls or
> casts --- I just don't want the system trying to use them to make
> sense of a bogus query.
>
> > I can cast to integer and float8 fine:
>
> I don't believe that those should be available as implicit casts either.
> They are, at the moment:
>
> regression=# select 33 || 44.0;
>  ?column?
> ----------
>  3344
> (1 row)
>
> Ugh.
>
>             regards, tom lane
>
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