Re: optimizing constant quals within outer joins

Phil Frost <indigo@bitglue.com> writes:
> The planner in fact can move the function around without changing the
> output.

Not when it's within the nullable side of an outer join --- moving a
WHERE clause up out of that would make the difference between no row
out, and a null-extended row out, which are certainly not the same.

I'm not sure why it's not pulling up from the left side of the left join
though.  That might be a bug.  What PG version is this exactly?

Of course the real question is why is your app generating such poorly
phrased queries ;-)
        regards, tom lane