Re: Adjust error message for CREATE STATISTICS to account for expressions

On Mon, 30 Mar 2026 10:21:54 +0700
John Naylor <johncnaylorls@gmail.com> wrote:

> On Sat, Mar 28, 2026 at 1:04 PM Yugo Nagata <nagata@sraoss.co.jp> wrote:
> >
> > On Fri, 27 Mar 2026 09:50:07 +0000
> > Dean Rasheed <dean.a.rasheed@gmail.com> wrote:
> 
> > > If we were to give more detail, it should probably be to point out
> > > that regular statistics will already be built for single columns,
> > > which is why single-column extended statistics would be redundant. So
> > > perhaps something like this:
> > >
> > > Error: cannot create extended statistics on a single column
> > > Detail: Univariate statistics are already built for each individual
> > > table column.
> >
> > That makes sense to me.
> >
> > Using an errdetail to explain the reason sounds reasonable.
> 
> Works for me.
> 
> > > > On Fri, 27 Mar 2026 07:45:37 +0700
> > > > John Naylor <johncnaylorls@gmail.com> wrote:
> > > > > Looking elsewhere in this file, however, I
> > > > > do see some messages with "cannot do X because ....", and I'd be more
> > > > > motivated to turn those "because" phrases into errdetails.
> 
> Did you also want to try tackling this while we're here?

Yes, that sounds good to me.

In particular, the following suggestion from Dean Rasheed seems like a
good approach:

> Error: cannot create extended statistics on a single column
> Detail: Univariate statistics are already built for each individual
> table column

Regards,
Yugo Nagata

-- 
Yugo Nagata <nagata@sraoss.co.jp>