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Update FAQ.

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Bruce Momjian
2001-01-22 06:27:41 +00:00
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doc/src/FAQ/FAQ.html
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@ -1224,21 +1224,26 @@ Lobby your company to join W3C, see http://www.w3.org/Consortium
<H4><A name="4.24">4.24</A>) How do I do an <I>outer</I> join?<BR>
</H4>
<P>PostgreSQL 7.1 and later supports outer joins. Here is an
example:</P>
<P>PostgreSQL 7.1 and later supports outer joins. Here are two
examples:</P>
<PRE>
SELECT *
FROM t1 LEFT OUTER JOIN t2 ON (t1.col = t2.col);
</PRE>
or
<PRE>
SELECT *
FROM t1 LEFT OUTER JOIN t2 USING (col);
</PRE>
This will join t1.col to t2.col, and return any unjoined rows in t1
with <SMALL>NULL</SMALL> values for t2 columns. A
<SMALL>RIGHT</SMALL> join would return unjoined rows of table t2. A
<SMALL>FULL</SMALL> join would return unjoined rows from t1 and t2.
The word <SMALL>OUTER</SMALL> is optional and is assumed in
<SMALL>LEFT</SMALL>, <SMALL>RIGHT</SMALL>, and <SMALL>FULL</SMALL>
joins. Ordinary joins are called <SMALL>INNER</SMALL> joins.<BR>
<BR>
In previous releases, outer joins can be simulated using
These identical queries join t1.col to t2.col, and return any
unjoined rows in t1. A <SMALL>RIGHT</SMALL> join would return
unjoined rows of table t2. A <SMALL>FULL</SMALL> join would return
unjoined rows from t1 and t2. The word <SMALL>OUTER</SMALL> is
optional and is assumed in <SMALL>LEFT</SMALL>,
<SMALL>RIGHT</SMALL>, and <SMALL>FULL</SMALL> joins. Ordinary joins
are called <SMALL>INNER</SMALL> joins.</P>
<P>In previous releases, outer joins can be simulated using
<SMALL>UNION</SMALL> and <SMALL>NOT IN</SMALL>. For example, when
joining <I>tab1</I> and <I>tab2,</I> the following query does an
<I>outer</I> join of the two tables:<BR>