Re: Why lower's not accept an AS declaration ?

Hi,

An to be more precise what I exactly want to do :

select
case when 'now' between t.begin and t.end then t.login else 'None' end as log
from my_table t
order by lower(log);

Is it an example more realistic for you to make an order by lower of something
as an alias ?

Regards,

Le Lundi 18 Août 2003 13:15, Darko Prenosil a écrit :
> On Monday 18 August 2003 13:04, Darko Prenosil wrote:
> > On Monday 18 August 2003 10:20, Hervé Piedvache wrote:
> > > Hi,
> > >
> > > May be my question is stupid ... but I'm a little suprised :
> > >
> > > SELECT id_letter as letter from my_table;
> > >
> > > letter
> > > -----
> > > B
> > > C
> > > a
> > > A
> > >
> > > SELECT id_letter as letter from my_table order by letter;
> > >
> > > letter
> > > -----
> > > A
> > > B
> > > C
> > > a
> > >
> > > SELECT id_letter as letter from my_table order by lower(letter);
> > >
> > > ERROR:  Attribute "letter" not found
> >
> > Why did you change column name to "letter" in last query, and all the
> > other queries have "id_letter" as column name. What is table structure
> > exactly ? I assume that You don't have column with "letter" at all.
> >
> > Regards !
>
> OK, now I see exactly the mistake You are making:
>
>     SELECT id_letter as letter from my_table order by lower(id_letter);
>
> would be correct query, because "letter" is only alias for result column,
> not column in "my_table". Sorry I didn't see it first time.
>
> Regards !
>
> ---------------------------(end of broadcast)---------------------------
> TIP 9: the planner will ignore your desire to choose an index scan if your
>       joining column's datatypes do not match

--
Hervé Piedvache

Elma Ingénierie Informatique
6 rue du Faubourg Saint-Honoré
F-75008 - Paris - France
Pho. 33-144949901
Fax. 33-144949902