Subject Re: [firebird-support] LEFT JOIN much faster than JOIN
Author Louis Kleiman (SSTMS, Inc.)
But LEFT OUTER JOIN may cause the optimizer to scan through the table for
which all rows are being included in physical order while the INNER JOIN
might cause a plan where rows are read based on a scan through an index. If
rows aren't being filtered out, I can see how this might speed up the query
execution.

Louis Kleiman


On Fri, Aug 2, 2013 at 8:04 AM, Josef KokeŇ° <j.kokes@...>wrote:

> **
>
>
> On 2.8.2013 13:59, Alexis Diel wrote:
> >
> >
> > but LEFT JOIN is diferente of JOIN...
> > - LEFT JOIN brings all the data filtered from the FROM table, and
> > - JOIN brings only the data that have the ON condition in the JOINED
> table.
>
> Which should make JOIN faster than LEFT JOIN, if anything, because it
> can (potentionally) filter out some records.
>
> Josef
>
>
>


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