diff options
author | Bruce Momjian | 2001-01-22 16:35:35 +0000 |
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committer | Bruce Momjian | 2001-01-22 16:35:35 +0000 |
commit | 0fada37f5d5a0148fb63f6dc02b50622601626a6 (patch) | |
tree | 6d07e151834f6def0f2c954172940b47708e194e /doc | |
parent | 7e0919136abd69715ab8f254e172d40c09ae6236 (diff) |
Update FAQ.
Diffstat (limited to 'doc')
-rw-r--r-- | doc/FAQ | 14 | ||||
-rw-r--r-- | doc/src/FAQ/FAQ.html | 11 |
2 files changed, 14 insertions, 11 deletions
@@ -948,7 +948,8 @@ SELECT * 4.24) How do I do an outer join? - PostgreSQL 7.1 and later supports outer joins. Here are two examples: + PostgreSQL 7.1 and later supports outer joins using the SQL standard + syntax. Here are two examples: SELECT * FROM t1 LEFT OUTER JOIN t2 ON (t1.col = t2.col); @@ -956,11 +957,12 @@ SELECT * SELECT * FROM t1 LEFT OUTER JOIN t2 USING (col); - 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. + These identical queries join t1.col to t2.col, and also return any + unjoined rows in t1 (those with no match in t2). A RIGHT join would + add unjoined rows of t2. A FULL join would return the matched rows + plus all 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 diff --git a/doc/src/FAQ/FAQ.html b/doc/src/FAQ/FAQ.html index 2ef4f1eceee..420754e2e6f 100644 --- a/doc/src/FAQ/FAQ.html +++ b/doc/src/FAQ/FAQ.html @@ -1224,8 +1224,8 @@ 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 are two - examples:</P> + <P>PostgreSQL 7.1 and later supports outer joins using the SQL + standard syntax. Here are two examples:</P> <PRE> SELECT * FROM t1 LEFT OUTER JOIN t2 ON (t1.col = t2.col); @@ -1235,9 +1235,10 @@ or SELECT * FROM t1 LEFT OUTER JOIN t2 USING (col); </PRE> - 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 + These identical queries join t1.col to t2.col, and also return any + unjoined rows in t1 (those with no match in t2). A + <SMALL>RIGHT</SMALL> join would add unjoined rows of t2. A + <SMALL>FULL</SMALL> join would return the matched rows plus all 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 |