Re: Better error message for select_common_type()

[Peter Eisentraut <peter_e(at)gmx(dot)net>]

Tom Lane wrote:
> +1 on using the parser location mechanism and avoiding the
> terminology problem altogether.

I figured we would let the parser only point to the UNION or VALUES or 
whatever word.  It would be fairly cumbersome to drag the individual 
expression positions down into select_common_value() for full 
precision.

> I fear though that we're not set up 
> to have multiple locations in one error report.  Will it be
> sufficient if we point at one of the two offending expressions?  (I'd
> guess pointing at the second makes the most sense, if feasible.)

I don't think that would help.  In the example I was looking at 90 
expression and I had no idea in most cases what their results types 
are, so if it tells me that the 15th expression somewhere doesn't 
match, I would need to know which is the other mismatching one.

-- 
Peter Eisentraut
http://developer.postgresql.org/~petere/