Re: Join efficiency

Russ Brown wrote:

> >> SELECT * FROM a, b WHERE a.x=b.x;

> >> SELECT * FROM a JOIN b ON a.x=b.x;

> That being the case, would it be true to say that with recent versions of
> PostgreSQL they both perform identically, meaning the second could be
> considered preferable due to its self-documenting nature (and consistency
> with the OUTER JOIN syntax)?

Assuming join_collapse_limit is at it's default or set higher...

As far as I can say from reading the documentation, following the hackers
list and trying out myself: yes, both versions should yield the same
optimized query plan and are therefore equal performance wise.

You can just use the one you prefer.

Best Regards,
Michael Paesold