Date: Tue, 15 Jan 2019 08:37:37 +0200
From: Eugen Konkov <kes-kes@yandex.ru>
Message-ID: <1382435334.20190115083737@yandex.ru>
To: Tom Lane <tgl@sss.pgh.pa.us>
CC: pgsql-docs@lists.postgresql.org
Subject: Re: DOC not so clear
In-Reply-To: <25974.1547482531@sss.pgh.pa.us>
References: <154747695538.22759.12913505368136831904@wrigleys.postgresql.org>
 <25974.1547482531@sss.pgh.pa.us>
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Hello Tom,

Monday, January 14, 2019, 6:15:31 PM, you wrote:

> =?utf-8?q?PG_Doc_comments_form?= <noreply@postgresql.org> writes:
>> https://www.postgresql.org/docs/current/queries-table-expressions.html#QUERIES-LATERAL

>>> The resulting row(s) are joined as usual with the rows they were computed
>>> from.

>> Here is not so clear what 'joined as usual' mean.

> Why not?

Advanced users may understand that, but from my beginner point of view
this  is  not. I do not understand that sentence until read whole text
and   about   LEFT   JOIN   LATERAL.   Even   now  'usual'  may  mean:
CROSS/RIGHT/FULL??


>> Probably DOC should explicitly say that if LATERAL function return empty set
>> then current row is excluded from result set

> That would be wrong for "LEFT JOIN LATERAL ...", so it does not seem
> like an improvement.

LATERAL != LEFT JOIN LATERAL
it would be more clear if DOC will be more explicit.


>                         regards, tom lane
-- 
Best regards,
Eugen Konkov