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Old 04-12-2008, 03:15 AM
Tom Lane
 
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Default 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

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