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Update FAQ.

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Bruce Momjian
2001-01-22 06:27:41 +00:00
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@ -948,15 +948,20 @@ SELECT *
4.24) How do I do an outer join?
PostgreSQL 7.1 and later supports outer joins. Here is an example:
PostgreSQL 7.1 and later supports outer joins. Here are two examples:
SELECT *
FROM t1 LEFT OUTER JOIN t2 ON (t1.col = t2.col);
or
SELECT *
FROM t1 LEFT OUTER JOIN t2 USING (col);
This will join t1.col to t2.col, and return any unjoined rows in t1
with NULL values for t2 columns. A RIGHT join would return unjoined
rows of table t2. A FULL join would return unjoined rows from t1 and
t2. The word OUTER is optional and is assumed in LEFT, RIGHT, and FULL
joins. Ordinary joins are called INNER joins.
These identical queries join t1.col to t2.col, and return any unjoined
rows in t1. A RIGHT join would return unjoined rows of table t2. A
FULL join would return unjoined rows from t1 and t2. The word OUTER is
optional and is assumed in LEFT, RIGHT, and FULL joins. Ordinary joins
are called INNER joins.
In previous releases, outer joins can be simulated using UNION and NOT
IN. For example, when joining tab1 and tab2, the following query does
an outer join of the two tables: