|Subject||Re: [firebird-support] in vs exist|
> > > to quote Celkoimplementation
> > > "An EXISTS predicate can use indexes to find.. or fail, whereas the IN
> > > predicate ofen has to build the results of the subquery in a working
> > >
> > > not sure exactly how FB is optimised in this regard
> >Celko is talking rubbish here. "can use indexes" -> this is
> >defined. How an engine handles whatever statement has nothing to doblindness
> >with the logical operator "EXISTS" or "IN".
> True, Celko uses Oracle for his examples. He does have a certain
> with regard to standard SQL and implementation-specific stuff.I guess we all have our "good" moments :-)
> worth paying attention to, esp. in the "Puzzles" stuff.