Re: Avoid casting NULLs in UNION...

OK Albe,

thanks for info

2013/2/1 Albe Laurenz <laurenz(dot)albe(at)wien(dot)gv(dot)at>

> Marko Rihtar wrote:
> > maybe you can help me with this issue.
> > Here is an example
> >
> > SELECT NULL::integer
> > UNION ALL
> > SELECT NULL
> > UNION ALL
> > SELECT 123
> >
> > For this sql to work i have to cast NULL to integer.
> > I was wondering if there exists some configuration parameter at database
> level that can be used to
> > avoid this need for explicit casting?
>
> Not that I know of.
>
> The behaviour is well defined and documented, see
> http://www.postgresql.org/docs/current/static/typeconv-union-case.html
>
> The UNIONs are computed left to right,
> and the data type in the first UNION resolves to "text"
> according to rule 2 of the page given above.
>
> You can reorder the UNIONs or use parentheses.
>
> Yours,
> Laurenz Albe
>