7.2. Table Expressions suggestion about NATURAL JOIN

From: Grzegorz Szpetkowski <gszpetkowski(at)gmail(dot)com>
To: pgsql-docs(at)postgresql(dot)org
Subject: 7.2. Table Expressions suggestion about NATURAL JOIN
Date: 2011-05-18 01:47:00
Message-ID: 201105192217.p4JMHVmf003186@mxv09.wellsfargo.com
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http://www.postgresql.org/docs/9.0/static/queries-table-expressions.html
http://www.postgresql.org/docs/9.0/static/sql-select.html

Respectively:

"Finally, NATURAL is a shorthand form of USING: it forms a USING list
consisting of all column names that appear in both input tables. As
with USING, these columns appear only once in the output table."

and

"NATURAL is shorthand for a USING list that mentions all columns in
the two tables that have the same names."

To make that comprehensive you can add something like: "Note that if
there is no any "shared" column between tables, then NATURAL JOIN acts
like ON TRUE (that is, tables are cross-joined)", because it's not
obvious.

thanks & regards,
greg szpetkowski

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Next Message Grzegorz Szpetkowski 2011-05-18 01:52:35 Re: 7.2. Table Expressions suggestion about NATURAL JOIN
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