Re: simplifying SQL - Mailing list pgsql-general

From Richard Huxton
Subject Re: simplifying SQL
Date
Msg-id 45CAE46C.7010603@archonet.com
Whole thread Raw
In response to simplifying SQL  (garry saddington <garry@schoolteachers.co.uk>)
List pgsql-general
garry saddington wrote:
> I have this query which essentially returns records that exist in one
> table (studentclass) and not another (effortandattainment) to check when
> teachers have entered their student grades.
>
> select

> from studentclass left join effortandattainment

> and studentclass.classid not in (

> I was wondering whether a simpler method exists to do the same thing or
> is this OK.

The formatting on the query isn't great, but I can't quite see what the
"left join" is doing with the "not in" too. I'd probably just have the
left join and check that "effortandattainment.classid IS NULL".

--
   Richard Huxton
   Archonet Ltd

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