Re: Help with query

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Тема Re: Help with query
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Msg-id c507d6de04081209535086708e@mail.gmail.com
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Ответ на Re: Help with query  (Josh Berkus <josh@agliodbs.com>)
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Many thanks Josh for the solution and the advice...

On Wed, 11 Aug 2004 21:48:50 -0700, Josh Berkus <josh@agliodbs.com> wrote:
> Ryan,
>
> > select c.user_id, a.user_id from athletes a, coaches c,
> > coaching_relationships cr where a.athlete_id = cr.athlete_id and
> > c.coach_id = cr.coach_id;
>
> You're close:
>
> select cuser.username as coach, auser.username as athlete
> from athletes, coaches, coaching_relationships co_rel,
>         users cuser, users auser
> where athletes.athlete_id = co_rel.athlete_id
>         and coaches.coach_id = co_rel.coach_id
>         and coaches.user_id = cuser.user_id
>         and athletes.user_id = auser.user_id
> order by cuser.username, auser.username
>
> And some unsolicited advice: don't abbreviate table names which are less than
> 10 characters.  When you have to revisit these queries in 9 months, you won't
> want to see all those "c" and "a" and "a1" tablename aliases.    It's like
> using programming variables named "x" and "y".
>
> --
> Josh Berkus
> Aglio Database Solutions
> San Francisco
>

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