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

Jackson, why do you prefer to mix the eggs and balls?
If you want to know HOW OFTEN the name is used in your database
it doesn't metter if it has a different ID. Second, from Patrick's
example is not seen that he will use duplicated names, and I think
he uses numbers just to save a place, so for which reason did you add
the record 'toto' with number 4? An third, any fields used in GROUP BY
clause
must to be present in SELECT clause (according to SQL standard), that's
why I sad
your query will never work and if it works under PSQL - we have a bug...

Best regards!
(dim)


Jackson, DeJuan wrote:
>
> djackson=> create table t1 (i SERIAL, n TEXT);
> NOTICE:  CREATE TABLE will create implicit sequence t1_i_seq for SERIAL
> column t1.i
> NOTICE:  CREATE TABLE/UNIQUE will create implicit index t1_i_key for
> table t1
> CREATE
> djackson=> insert into t1(n) VALUES ('toto');
> INSERT 231199 1
> djackson=> insert into t1(n) VALUES ('tutu');
> INSERT 231200 1
> djackson=> insert into t1(n) VALUES ('titi');
> INSERT 231201 1
> djackson=> insert into t1(n) VALUES ('toto');
> INSERT 231202 1
> djackson=> create table t2 (i INT, tag TEXT);
> CREATE
> djackson=> insert into t2(i, tag) VALUES(1, 'alpha');
> INSERT 231213 1
> djackson=> insert into t2(i, tag) VALUES(1, 'beta');
> INSERT 231214 1
> djackson=> insert into t2(i, tag) VALUES(2, 'gamma');
> INSERT 231215 1
> djackson=> insert into t2(i, tag) VALUES(3, 'zeta');
> INSERT 231216 1
> djackson=> insert into t2(i, tag) VALUES(3, 'epsilon');
> INSERT 231217 1
> djackson=> insert into t2(i, tag) VALUES(4, 'omega');
> INSERT 231218 1
> djackson=> select * from t1;
> i|n
> -+----
> 1|toto
> 2|tutu
> 3|titi
> 4|toto
> (4 rows)
>
> djackson=> select * from t2;
> i|tag
> -+-------
> 1|alpha
> 1|beta
> 2|gamma
> 3|zeta
> 3|epsilon
> 4|omega
> (6 rows)
> *****************MY QUERY****************
> djackson=> select t1.n, count(t2.tag) from t1, t2 where t1.i=t2.i group
> by t1.i, t1.name;
> ERROR:  func_get_detail: No such attribute or function 'name'
> djackson=> select t1.n, count(t2.tag) from t1, t2 where t1.i=t2.i group
> by t1.i, t1.n;
> n   |count
> ----+-----
> toto|    2
> tutu|    1
> titi|    2
> toto|    1
> (4 rows)
> ****************YOUR QUERY AS WRITTEN TO JAN**************
> djackson=> select n, count(*) as how_often from t1, t2 where t1.i=t2.i
> group by n;
> n   |how_often
> ----+---------
> titi|        2
> toto|        3
> tutu|        1
> (3 rows)
>
> Get the point?
>         -DEJ
> > -----Original Message-----
> > From: Dimitri [mailto:dimitri@france.Sun.COM]
> > Sent: Thursday, February 04, 1999 4:14 PM
> > To: Jackson, DeJuan
> > Cc: pat@patoche.org; pgsql-sql@postgreSQL.org
> > Subject: Re: [SQL] problem with join & count
> >
> >
> > Jackson, DeJuan wrote:
> > >
> > > try:
> > > SELECT t1.name, count(t2.tag)
> > >   FROM t1, t2
> > >  WHERE t1.number = t2.number
> > >  GROUP BY t1.number, t1.name
> > ______________^
> > your query will never work :)), you have to miss t1.number...
> >
> > Best regards!
> > (dim)
> >
> > >
> > >         -DEJ
> > >
> > > > -----Original Message-----
> > > > From: pat@patoche.org [mailto:pat@patoche.org]
> > > > Sent: Thursday, February 04, 1999 2:39 PM
> > > > To: pgsql-sql@postgreSQL.org
> > > > Subject: [SQL] problem with join & count
> > > >
> > > >
> > > > Hi,
> > > >
> > > > I don't succeed to build an SQL to do the task i describe below.
> > > > If someone can helps, thanks in advance.
> > > >
> > > > I have two tables
> > > >
> > > > number  | name
> > > > --------------
> > > >  1      | toto
> > > >  2      | titi
> > > >  3      | tutu
> > > >
> > > > (here the number is a primary key)
> > > >
> > > > and
> > > >
> > > > number  |  tag
> > > > ---------------
> > > >  1      | alpha
> > > >  1      | beta
> > > >  2      | gamma
> > > >  3      | zeta
> > > >  3      | epsilon
> > > >
> > > > the number in the left column is the same of the number in
> > > > the first table,
> > > > but can appear in that second table many times.
> > > >
> > > > 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.
> > > >
> > > > Thanks a lot for your help.
> > > >
> > > > Patrick
> > > >
> > > > /\//\/\/\\/\/\//\/\\/\/\\/\\/\//\/\\/\//\/\\/\//\/\\/\//\/\\
> > > > Patrick M.   pat@patoche.org    http://www.patoche.org/
> > > >
> > > >
> >
> > --
> > =====================================================
> >  Dimitri KRAVTCHUK  (dim)           Sun Microsystems
> >  Benchmark Engineer                 France
> >  dimitri@France.Sun.COM
> > =====================================================
> >

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