Re: EXISTS vs IN vs OUTER JOINS - Mailing list pgsql-performance

From Josh Berkus
Subject Re: EXISTS vs IN vs OUTER JOINS
Date
Msg-id 200212191102.39785.josh@agliodbs.com
Whole thread Raw
In response to Re: EXISTS vs IN vs OUTER JOINS  (jasiek@klaster.net)
Responses Re: EXISTS vs IN vs OUTER JOINS  (jasiek@klaster.net)
List pgsql-performance
Tomasz,

> > This will not get you the same result as the above.  It will get you
> > all rows from t+f where a record is present in f and has (or does not
> > have) a NULL value for f.id.   While this type of query works in MS
> > Access, it will not work in SQL92/99-commpliant databases.
>
> filter_table does not contain null fields. It has only two states: it
> has row
> or it hasn't row coresponding to row in some_table.
>
> And now, which one is better?

You're not listening.  I said that LEFT JOIN won't work.  At all.

Please re-read the paragraph above, which explains why.

--
-Josh Berkus
 Aglio Database Solutions
 San Francisco


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