Thread: get only rows for latest version of contents
Hi everybody.
I have a table like that (i simplified it):
CREATE TABLE business { idnode integer not null, version_no integer, c1 text, c2 text, c3 text
}
With a unique index in (idnode,version_no).
This table records many version from contents identified by idnode where
texts may be different.
So i can have:
Idnode | version_no | c1 | c2 | c3
111 | 2 | foo1 | foo2 | foo3
111 | 1 | fee1 | foo2 | foo3
111 | null | fee1 | fee2 | fee3
222 | null | too1 | too2 | too3
333 | 1 | xoo1 | xoo2 | xoo3
333 | null | yoo1 | yoo2 | yee3
I want to select all columns but only for last (greatest) version of each
content. So I want a result like:
Idnode | version_no | c1 | c2 | c3
111 | 2 | foo1 | foo2 | foo3
222 | null | too1 | too2 | too3
333 | 1 | xoo1 | xoo2 | xoo3
If i do:
SELECT idnode, max(version_no) FROM business
GROUP BY idnode ORDER BY idnode;
I get effectively only last version:
Idnode | version_no
111 | 2
222 | null
333 | 1
But as soon that i want to get texts, I don't know how to build the SQL.
In each SQL i tested i've been forced to put text column in a group by since
i used aggregate for version_no:
SELECT idnode, max(version_no), c1, c2, c3 FROM BUSINESS
GROUP BY idnode, c1, c2, c3 ORDER BY idnode;
But with that SQL, because of the group by and different values in text i
get
Idnode | version_no | c1 | c2 | c3
111 | 2 | foo1 | foo2 | foo3
111 | 1 | fee1 | foo2 | foo3
111 | null | fee1 | fee2 | fee3
222 | null | too1 | too2 | too3
333 | 1 | xoo1 | xoo2 | xoo3
333 | null | yoo1 | yoo2 | yee3
As we can't do aggregate in join neither in where, i can't get what i want.
Anybody could help me to build proper SQL ?
Thx for your answers.
Sébastien.
Hi!
not quick mut works
select * from business b1
where b1.version_no = (SELECT max(version_no) FROM business b2. where b2.idnode = b1.idnode
)
If you want to make this quiry faster du a regular join
select b1.* from business b1, (SELECT max(version_no) FROM business b2. where b2.idnode = b1.idnode
)as b2
where b1.idnode = b2.idnode and b1.version_no = b2.version_nr
Regards Chris
PS written without running any sql, maybe there are some syntax issues, but i am shure you will figure these out :-)
On Wed, October 24, 2007 11:29 am, Sébastien Meudec wrote:
> Hi everybody.
>
> I have a table like that (i simplified it):
> CREATE TABLE business {
> idnode integer not null,
> version_no integer,
> c1 text,
> c2 text,
> c3 text
> }
> With a unique index in (idnode,version_no).
>
> This table records many version from contents identified by idnode where
> texts may be different.
> So i can have:
> Idnode | version_no | c1 | c2 | c3
> 111 | 2 | foo1 | foo2 | foo3
> 111 | 1 | fee1 | foo2 | foo3
> 111 | null | fee1 | fee2 | fee3
> 222 | null | too1 | too2 | too3
> 333 | 1 | xoo1 | xoo2 | xoo3
> 333 | null | yoo1 | yoo2 | yee3
>
> I want to select all columns but only for last (greatest) version of each
> content. So I want a result like:
> Idnode | version_no | c1 | c2 | c3
> 111 | 2 | foo1 | foo2 | foo3
> 222 | null | too1 | too2 | too3
> 333 | 1 | xoo1 | xoo2 | xoo3
>
> If i do:
> SELECT idnode, max(version_no) FROM business
> GROUP BY idnode ORDER BY idnode;
>
> I get effectively only last version:
> Idnode | version_no
> 111 | 2
> 222 | null
> 333 | 1
>
> But as soon that i want to get texts, I don't know how to build the SQL.
> In each SQL i tested i've been forced to put text column in a group by
> since
> i used aggregate for version_no:
> SELECT idnode, max(version_no), c1, c2, c3 FROM BUSINESS
> GROUP BY idnode, c1, c2, c3 ORDER BY idnode;
>
> But with that SQL, because of the group by and different values in text i
> get
> Idnode | version_no | c1 | c2 | c3
> 111 | 2 | foo1 | foo2 | foo3
> 111 | 1 | fee1 | foo2 | foo3
> 111 | null | fee1 | fee2 | fee3
> 222 | null | too1 | too2 | too3
> 333 | 1 | xoo1 | xoo2 | xoo3
> 333 | null | yoo1 | yoo2 | yee3
>
> As we can't do aggregate in join neither in where, i can't get what i
> want.
>
> Anybody could help me to build proper SQL ?
>
> Thx for your answers.
> Sébastien.
>
>
>
> ---------------------------(end of broadcast)---------------------------
> TIP 7: You can help support the PostgreSQL project by donating at
>
> http://www.postgresql.org/about/donate
>
--
cu
Chris
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Thx a lot Chris.
In fact the correct SQL was (rewritten with inner join because of it is
required by my api):
select b1.*
from business b1
inner join (select idnode,max(version_no) as version_no from business group by idnode) as b2
on b1.idnode = b2.idnode and (b1.version_no = b2.version_no or b2.version_no is null)
Regards,
Seb.
> -----Message d'origine-----
> De : pgsql-sql-owner@postgresql.org [mailto:pgsql-sql-
> owner@postgresql.org] De la part de Christian Kindler
> Envoyé : mercredi 24 octobre 2007 11:55
> À : Sébastien Meudec
> Cc : pgsql-sql@postgresql.org
> Objet : Re: [SQL] get only rows for latest version of contents
>
> Hi!
>
> not quick mut works
>
> select * from business b1
> where b1.version_no = (SELECT max(version_no) FROM business b2.
> where b2.idnode = b1.idnode
> )
>
> If you want to make this quiry faster du a regular join
>
> select b1.*
> from business b1,
> (SELECT max(version_no) FROM business b2.
> where b2.idnode = b1.idnode
> ) as b2
> where b1.idnode = b2.idnode
> and b1.version_no = b2.version_nr
>
> Regards Chris
>
> PS written without running any sql, maybe there are some syntax issues,
> but i am shure you will figure these out :-)
>
>
>
> On Wed, October 24, 2007 11:29 am, Sébastien Meudec wrote:
> > Hi everybody.
> >
> > I have a table like that (i simplified it):
> > CREATE TABLE business {
> > idnode integer not null,
> > version_no integer,
> > c1 text,
> > c2 text,
> > c3 text
> > }
> > With a unique index in (idnode,version_no).
> >
> > This table records many version from contents identified by idnode where
> > texts may be different.
> > So i can have:
> > Idnode | version_no | c1 | c2 | c3
> > 111 | 2 | foo1 | foo2 | foo3
> > 111 | 1 | fee1 | foo2 | foo3
> > 111 | null | fee1 | fee2 | fee3
> > 222 | null | too1 | too2 | too3
> > 333 | 1 | xoo1 | xoo2 | xoo3
> > 333 | null | yoo1 | yoo2 | yee3
> >
> > I want to select all columns but only for last (greatest) version of
> each
> > content. So I want a result like:
> > Idnode | version_no | c1 | c2 | c3
> > 111 | 2 | foo1 | foo2 | foo3
> > 222 | null | too1 | too2 | too3
> > 333 | 1 | xoo1 | xoo2 | xoo3
> >
> > If i do:
> > SELECT idnode, max(version_no) FROM business
> > GROUP BY idnode ORDER BY idnode;
> >
> > I get effectively only last version:
> > Idnode | version_no
> > 111 | 2
> > 222 | null
> > 333 | 1
> >
> > But as soon that i want to get texts, I don't know how to build the SQL.
> > In each SQL i tested i've been forced to put text column in a group by
> > since
> > i used aggregate for version_no:
> > SELECT idnode, max(version_no), c1, c2, c3 FROM BUSINESS
> > GROUP BY idnode, c1, c2, c3 ORDER BY idnode;
> >
> > But with that SQL, because of the group by and different values in text
> i
> > get
> > Idnode | version_no | c1 | c2 | c3
> > 111 | 2 | foo1 | foo2 | foo3
> > 111 | 1 | fee1 | foo2 | foo3
> > 111 | null | fee1 | fee2 | fee3
> > 222 | null | too1 | too2 | too3
> > 333 | 1 | xoo1 | xoo2 | xoo3
> > 333 | null | yoo1 | yoo2 | yee3
> >
> > As we can't do aggregate in join neither in where, i can't get what i
> > want.
> >
> > Anybody could help me to build proper SQL ?
> >
> > Thx for your answers.
> > Sébastien.
> >
> >
> >
> > ---------------------------(end of broadcast)---------------------------
> > TIP 7: You can help support the PostgreSQL project by donating at
> >
> > http://www.postgresql.org/about/donate
> >
> --
> cu
> Chris
>
> Ist Ihr Browser Vista-kompatibel? Jetzt die neuesten
> Browser-Versionen downloaden: http://www.gmx.net/de/go/browser
>
> ---------------------------(end of broadcast)---------------------------
> TIP 7: You can help support the PostgreSQL project by donating at
>
> http://www.postgresql.org/about/donate
On Oct 25, 2007, at 1:50 AM, Sébastien Meudec wrote:
> Thx a lot Chris.
>
> In fact the correct SQL was (rewritten with inner join because of
> it is
> required by my api):
>
> select b1.*
> from business b1
> inner join (select idnode,max(version_no) as version_no from business
> group by idnode) as b2
> on b1.idnode = b2.idnode and
> (b1.version_no = b2.version_no or b2.version_no is null)
>
> Regards,
> Seb.
>
>
>> -----Message d'origine-----
>> De : pgsql-sql-owner@postgresql.org [mailto:pgsql-sql-
>> owner@postgresql.org] De la part de Christian Kindler
>> Envoyé : mercredi 24 octobre 2007 11:55
>> À : Sébastien Meudec
>> Cc : pgsql-sql@postgresql.org
>> Objet : Re: [SQL] get only rows for latest version of contents
>>
>> Hi!
>>
>> not quick mut works
>>
>> select * from business b1
>> where b1.version_no = (SELECT max(version_no) FROM business b2.
>> where b2.idnode = b1.idnode
>> )
>>
>> If you want to make this quiry faster du a regular join
>>
>> select b1.*
>> from business b1,
>> (SELECT max(version_no) FROM business b2.
>> where b2.idnode = b1.idnode
>> ) as b2
>> where b1.idnode = b2.idnode
>> and b1.version_no = b2.version_nr
>>
>> Regards Chris
>>
>> PS written without running any sql, maybe there are some syntax
>> issues,
>> but i am shure you will figure these out :-)
>>
>>
>>
>> On Wed, October 24, 2007 11:29 am, Sébastien Meudec wrote:
>>> Hi everybody.
>>>
>>> I have a table like that (i simplified it):
>>> CREATE TABLE business {
>>> idnode integer not null,
>>> version_no integer,
>>> c1 text,
>>> c2 text,
>>> c3 text
>>> }
>>> With a unique index in (idnode,version_no).
>>>
>>> This table records many version from contents identified by
>>> idnode where
>>> texts may be different.
>>> So i can have:
>>> Idnode | version_no | c1 | c2 | c3
>>> 111 | 2 | foo1 | foo2 | foo3
>>> 111 | 1 | fee1 | foo2 | foo3
>>> 111 | null | fee1 | fee2 | fee3
>>> 222 | null | too1 | too2 | too3
>>> 333 | 1 | xoo1 | xoo2 | xoo3
>>> 333 | null | yoo1 | yoo2 | yee3
>>>
>>> I want to select all columns but only for last (greatest) version of
>> each
>>> content. So I want a result like:
>>> Idnode | version_no | c1 | c2 | c3
>>> 111 | 2 | foo1 | foo2 | foo3
>>> 222 | null | too1 | too2 | too3
>>> 333 | 1 | xoo1 | xoo2 | xoo3
>>>
>>> If i do:
>>> SELECT idnode, max(version_no) FROM business
>>> GROUP BY idnode ORDER BY idnode;
>>>
>>> I get effectively only last version:
>>> Idnode | version_no
>>> 111 | 2
>>> 222 | null
>>> 333 | 1
>>>
>>> But as soon that i want to get texts, I don't know how to build
>>> the SQL.
>>> In each SQL i tested i've been forced to put text column in a
>>> group by
>>> since
>>> i used aggregate for version_no:
>>> SELECT idnode, max(version_no), c1, c2, c3 FROM BUSINESS
>>> GROUP BY idnode, c1, c2, c3 ORDER BY idnode;
>>>
>>> But with that SQL, because of the group by and different values
>>> in text
>> i
>>> get
>>> Idnode | version_no | c1 | c2 | c3
>>> 111 | 2 | foo1 | foo2 | foo3
>>> 111 | 1 | fee1 | foo2 | foo3
>>> 111 | null | fee1 | fee2 | fee3
>>> 222 | null | too1 | too2 | too3
>>> 333 | 1 | xoo1 | xoo2 | xoo3
>>> 333 | null | yoo1 | yoo2 | yee3
>>>
>>> As we can't do aggregate in join neither in where, i can't get
>>> what i
>>> want.
>>>
>>> Anybody could help me to build proper SQL ?
>>>
>>> Thx for your answers.
>>> Sébastien.
Here's another little trick that can come in handy for this:
SELECT DISTINCT ON (Idnode) Idnode, version_no, c1, c2, c3
FROM business
ORDER BY Idnode, version_no DESC;
Erik Jones
Software Developer | Emma®
erik@myemma.com
800.595.4401 or 615.292.5888
615.292.0777 (fax)
Emma helps organizations everywhere communicate & market in style.
Visit us online at http://www.myemma.com
Hi Erik
Thx for your suggestion.
I've done some tests and correct the order to get what i want.
In fact the order i would like to have is 3,2,1,null (null is a draft
version on my api).
But the order ASC gives 1,2,3,null
And the order DESC gives null,3,2,1
So i use order by -(version_no) that gives me 3,2,1,null
SELECT DISTINCT ON (Idnode) Idnode, version_no, c1, c2, c3
FROM business
GROUP BY Idnode, version_no, c1, c2, c3
ORDER BY Idnode, -(version_no) DESC;
But finally, when i have wanted to inject this way in my real big request it
gives me error:
SELECT DISTINCT ON expressions must match initial ORDER BY expressions
Because my api requires a different order and it seems idnode should be in
first of the order to be able to use DISTINCT ON.
So for now, i'll keep Chris solution.
I have not profile it with large tables but it's the only solution i have
for now ;)
Thx everybody.
Regards
Sebastien
> -----Message d'origine-----
> De : Erik Jones [mailto:erik@myemma.com]
> Envoyé : jeudi 25 octobre 2007 16:35
> À : Sébastien Meudec
> Cc : 'Christian Kindler'; pgsql-sql@postgresql.org
> Objet : Re: [SQL] get only rows for latest version of contents
>
>
> On Oct 25, 2007, at 1:50 AM, Sébastien Meudec wrote:
>
> > Thx a lot Chris.
> >
> > In fact the correct SQL was (rewritten with inner join because of
> > it is
> > required by my api):
> >
> > select b1.*
> > from business b1
> > inner join (select idnode,max(version_no) as version_no from business
> > group by idnode) as b2
> > on b1.idnode = b2.idnode and
> > (b1.version_no = b2.version_no or b2.version_no is null)
> >
> > Regards,
> > Seb.
> >
> >
> >> -----Message d'origine-----
> >> De : pgsql-sql-owner@postgresql.org [mailto:pgsql-sql-
> >> owner@postgresql.org] De la part de Christian Kindler
> >> Envoyé : mercredi 24 octobre 2007 11:55
> >> À : Sébastien Meudec
> >> Cc : pgsql-sql@postgresql.org
> >> Objet : Re: [SQL] get only rows for latest version of contents
> >>
> >> Hi!
> >>
> >> not quick mut works
> >>
> >> select * from business b1
> >> where b1.version_no = (SELECT max(version_no) FROM business b2.
> >> where b2.idnode = b1.idnode
> >> )
> >>
> >> If you want to make this quiry faster du a regular join
> >>
> >> select b1.*
> >> from business b1,
> >> (SELECT max(version_no) FROM business b2.
> >> where b2.idnode = b1.idnode
> >> ) as b2
> >> where b1.idnode = b2.idnode
> >> and b1.version_no = b2.version_nr
> >>
> >> Regards Chris
> >>
> >> PS written without running any sql, maybe there are some syntax
> >> issues,
> >> but i am shure you will figure these out :-)
> >>
> >>
> >>
> >> On Wed, October 24, 2007 11:29 am, Sébastien Meudec wrote:
> >>> Hi everybody.
> >>>
> >>> I have a table like that (i simplified it):
> >>> CREATE TABLE business {
> >>> idnode integer not null,
> >>> version_no integer,
> >>> c1 text,
> >>> c2 text,
> >>> c3 text
> >>> }
> >>> With a unique index in (idnode,version_no).
> >>>
> >>> This table records many version from contents identified by
> >>> idnode where
> >>> texts may be different.
> >>> So i can have:
> >>> Idnode | version_no | c1 | c2 | c3
> >>> 111 | 2 | foo1 | foo2 | foo3
> >>> 111 | 1 | fee1 | foo2 | foo3
> >>> 111 | null | fee1 | fee2 | fee3
> >>> 222 | null | too1 | too2 | too3
> >>> 333 | 1 | xoo1 | xoo2 | xoo3
> >>> 333 | null | yoo1 | yoo2 | yee3
> >>>
> >>> I want to select all columns but only for last (greatest) version of
> >> each
> >>> content. So I want a result like:
> >>> Idnode | version_no | c1 | c2 | c3
> >>> 111 | 2 | foo1 | foo2 | foo3
> >>> 222 | null | too1 | too2 | too3
> >>> 333 | 1 | xoo1 | xoo2 | xoo3
> >>>
> >>> If i do:
> >>> SELECT idnode, max(version_no) FROM business
> >>> GROUP BY idnode ORDER BY idnode;
> >>>
> >>> I get effectively only last version:
> >>> Idnode | version_no
> >>> 111 | 2
> >>> 222 | null
> >>> 333 | 1
> >>>
> >>> But as soon that i want to get texts, I don't know how to build
> >>> the SQL.
> >>> In each SQL i tested i've been forced to put text column in a
> >>> group by
> >>> since
> >>> i used aggregate for version_no:
> >>> SELECT idnode, max(version_no), c1, c2, c3 FROM BUSINESS
> >>> GROUP BY idnode, c1, c2, c3 ORDER BY idnode;
> >>>
> >>> But with that SQL, because of the group by and different values
> >>> in text
> >> i
> >>> get
> >>> Idnode | version_no | c1 | c2 | c3
> >>> 111 | 2 | foo1 | foo2 | foo3
> >>> 111 | 1 | fee1 | foo2 | foo3
> >>> 111 | null | fee1 | fee2 | fee3
> >>> 222 | null | too1 | too2 | too3
> >>> 333 | 1 | xoo1 | xoo2 | xoo3
> >>> 333 | null | yoo1 | yoo2 | yee3
> >>>
> >>> As we can't do aggregate in join neither in where, i can't get
> >>> what i
> >>> want.
> >>>
> >>> Anybody could help me to build proper SQL ?
> >>>
> >>> Thx for your answers.
> >>> Sébastien.
>
> Here's another little trick that can come in handy for this:
>
> SELECT DISTINCT ON (Idnode) Idnode, version_no, c1, c2, c3
> FROM business
> ORDER BY Idnode, version_no DESC;
>
> Erik Jones
>
> Software Developer | Emma®
> erik@myemma.com
> 800.595.4401 or 615.292.5888
> 615.292.0777 (fax)
>
> Emma helps organizations everywhere communicate & market in style.
> Visit us online at http://www.myemma.com
>