[Haskelldb-users] GROUP BY bug fix

[Justin B. <jgb...@gm...>]

On Thu, Jul 10, 2008 at 12:04 AM, Henning Thielemann
<has...@he...> wrote:
>
> SELECT C2 C
> FROM (SELECT C C2
>       FROM POINTS T1
>       GROUP BY C2) T1
>
>
> But the C2 after GROUP BY does not denote a column of a table. It may be
> replaced by C or the GROUP BY may be moved to the outer SELECT statement.
>

I've corrected this bug in the attached patch. It occurred because the
defaultSqlGroup function in Database.HaskellDB.Sql.Default did not
properly filter projected columns from its group by clause. I also
fixed a bug in defaultSqlProject where order by columns were not added
to the group by clause if they did not appear in a projection.

I added a few tests for the new cases which appear to work. Any
comments welcome!

Justin