Re: Ugly group by problem

O Markus Schaber έγραψε στις Mar 29, 2006 :

> Hi, Achilleus,
> 
> Achilleus Mantzios wrote:
> 
> > foodb=# SELECT qoo.foo2,sum(qoo.foo3) from (SELECT mt.link_id as 
> > foo,_int_union(array(select mt2.feat_id from markustest mt2 where 
> > mt2.link_id=mt.link_id order by mt2.feat_id),'{}') as foo2,other::int4 as 
> > foo3 from markustest mt) as qoo GROUP BY qoo.foo2;
> >   foo2  | sum
> > --------+-----
> >  {2}    |   1
> >  {5,23} |  13
> >  {23}   |  14
> > (3 rows)
> 
> This is much like I intended to do it, but using "select distinct" in
> the inner select as I don't have _int_union here, and using a temporary
> table to collect the sets of link ids.

Just some facts:

sort(uniq(int[])) has the same effect as select DISTINCT... ORDER BY
DISTINCT.  ORDER BY is ofcourse more intuitive and does not need 
contrib/intarray.

In fact , i dont even remember why i didnt write the query with 
DISTINCT... in the first place :)

> 
> Markus
> 
> 
> 

-- 
-Achilleus