Re: Casting Varchar to Numeric

On Tue, Nov 27, 2001 at 09:55:41AM -0000, Andy Marden wrote:
> Just undertaking a port of a small Data Warehouse-type batch load
> application from Oracle to PostgreSQL. It's common practice in such a system
> to load data into a staging table whose fields are typically all varying
> text. Then the conversion and mapping of the data is done as a second stage
> into the 'proper' tables.
>
> In Oracle, you can put a text field into a numeric field as long as it
> contains a number and teh conversion will be implicit (or you can simply
> specify to_number(value)) to make the conversion explicitly.
>
> In PostgreSQL, it seems that an error is thrown up if an implicit conversion
> is attempted, and the only explicit conversion seems to be to_number(value,
> format) which doesn't do what's needed generically enough.
>
> I can't believe that this isn't possible - can anyone point me in the right
> direction?

Well, it's a bit more complicated than that. For example, text -> int4 is
done. You do realise you can cast like value::type. For example:

select field::numeric(10,2);

Now, I'm not sure if you can do varchar -> numeric directly. I don't use
varchar anymore since there is no advantage over text but text is much
better supported.

HTH,
--
Martijn van Oosterhout <kleptog(at)svana(dot)org>
http://svana.org/kleptog/
> Terrorists can only take my life. Only my government can take my freedom.