Doc: clarify description of degenerate NATURAL joins.

Tom Lane <tgl@sss.pgh.pa.us>

Commit: 769eaef7600b0cc63bdc488428c4e01902261a73
Author: Tom Lane <tgl@sss.pgh.pa.us>
Date: 2017-07-20T16:41:41Z
Releases: 9.4.13
Doc: clarify description of degenerate NATURAL joins.

Claiming that NATURAL JOIN is equivalent to CROSS JOIN when there are
no common column names is only strictly correct if it's an inner join;
you can't say e.g. CROSS LEFT JOIN.  Better to explain it as meaning
JOIN ON TRUE, instead.  Per a suggestion from David Johnston.

Discussion: https://postgr.es/m/CAKFQuwb+mYszQhDS9f_dqRrk1=Pe-S6D=XMkAXcDf4ykKPmgKQ@mail.gmail.com

Files

PathChange+/−
doc/src/sgml/queries.sgml modified +2 −2
doc/src/sgml/ref/select.sgml modified +5 −2

Discussion