Re: Change JOIN tutorial to focus more on explicit joins

po 15. 3. 2021 v 3:48 odesílatel Thomas Munro <thomas.munro@gmail.com>
napsal:

> On Thu, Mar 11, 2021 at 2:06 AM David Steele <david@pgmasters.net> wrote:
> > On 12/1/20 3:38 AM, Jürgen Purtz wrote:
> > > OK. Patch attached.
>
> +    Queries which access multiple tables (including repeats) at once are
> called
>
> I'd write "Queries that" here (that's is a transatlantic difference in
> usage; I try to proofread these things in American mode for
> consistency with the rest of the language in this project, which I
> probably don't entirely succeed at but this one I've learned...).
>
> Maybe instead of "(including repeats)" it could say "(or multiple
> instances of the same table)"?
>
> +    For example, to return all the weather records together with the
> location of the
> +    associated city, the database compares the
> <structfield>city</structfield>
>      column of each row of the <structname>weather</structname> table with
> the
>      <structfield>name</structfield> column of all rows in the
> <structname>cities</structname>
>      table, and select the pairs of rows where these values match.
>
> Here "select" should agree with "the database" and take an -s, no?
>
> +    This syntax pre-dates the <literal>JOIN</literal> and
> <literal>ON</literal>
> +    keywords.  The tables are simply listed in the
> <literal>FROM</literal>,
> +    comma-separated, and the comparison expression added to the
> +    <literal>WHERE</literal> clause.
>
> Could we mention SQL92 somewhere?  Like maybe "This syntax pre-dates
> the JOIN and ON keywords, which were introduced by SQL-92".  (That's a
> "non-restrictive which", I think the clue is the comma?)
>

previous syntax should be mentioned too. An reader can find this syntax
thousands applications

Pavel


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