On Fri, 21 Mar 2014 06:54:21 +0100, Thomas Beckmann <[email protected]> wrote: > Thank you for your answer, Mark, > > my friend and collegue Frank (fsg) and I kept in mind, that at the prior > to the last FB-conference, we listend to an optimization talk of one of > the core devs (it must have been Dimitry ;-) ) and remembered that: > > - engine does not reorder joins for optimization purpose if left join > and straight join get mixed > - engine evaluates join before left join. > > This was, what made me assue, the expression would be evaluated like the > braced version. I did not check SQL standard definition yet, but it > seemed somewhat natural to me...
AFAIK those ordering rules only apply if you have multiple joins joining to the same table, in this case you define a string of joins from and therefor they are evaluated in order unless you apply braces. Mark
