Re: [SQL] problem with join & count - Mailing list pgsql-sql

From Dimitri
Subject Re: [SQL] problem with join & count
Date
Msg-id 36BA1ABD.31E18EFC@france.sun.com
Whole thread Raw
In response to Re: [SQL] problem with join & count  (jwieck@debis.com (Jan Wieck))
List pgsql-sql
Hm...

Why do be complex where you can be sample?

Your query is:

select name, count(*) as how_often
 from table1, table2
  where table1.number = table2.number
    group by name;

and that's all, folks!

P.S. Regarding your example, I can say that you are French! Isnt it? :))
"toto, titi" - very unique as names :))

Jan Wieck wrote:
>
> > i need an sql query that will return:
> >
> > name   |  how_often
> > -------------------
> >  toto  | 2
> >  titi  | 1
> >  tutu  | 2
> >
> > that is, the result table should contain all names present in the first table
> > and then the number of times the number associated with the name appears in
> > the second table.
>
>     Postgres  does not (and v6.5 will not) support outer joins or
>     subselects in the targetlist, what's required to do that in a
>     single SQL statement.
>
>     What  you  could  do  is using a SQL function that covers the
>     count() like this:
>
>         create function num_refs (int4) returns int4 as '
>             select count(*) from tab2 where id = $1;
>         ' language 'SQL';
>
>         select item_name, num_refs(id) as how_often from tab1;
>
>     I changed 'number' into id and name  into  item_name  because
>     both are reserved words.
>
> Jan
>
> --
>
> #======================================================================#
> # It's easier to get forgiveness for being wrong than for being right. #
> # Let's break this rule - forgive me.                                  #
> #======================================== jwieck@debis.com (Jan Wieck) #

--
=====================================================
 Dimitri KRAVTCHUK  (dim)           Sun Microsystems
 Benchmark Engineer                 France
 dimitri@France.Sun.COM
=====================================================

pgsql-sql by date:

Previous
From: "Jackson, DeJuan"
Date:
Subject: RE: [SQL] problem with join & count
Next
From: Dimitri
Date:
Subject: Re: [SQL] problem with join & count