Thread: RE: [SQL] problem with join & count
try:
SELECT t1.name, count(t2.tag)
FROM t1, t2
WHERE t1.number = t2.number
GROUP BY t1.number, t1.name
-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/
>
>
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 =====================================================
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