Re: find the number of row for each tables - Mailing list pgsql-novice

Hi,

You didn't made any link between your two tables, so this make a
cartesian product, that why it is very long, and you have to cancel it.

Re-try your select with the exact join condition between your 2 tables

Something like :
select count(a.id), count(b.id) from accounts a, subaccounts b
where a.id = b.a_id;

(if a_id is the id of accounts in subaccounts)

(sorry for my poor english)

Nicolas


D. Duccini wrote:
>
> Interesting, I just tried the following:
>
> actmgr=> select count(a.id), count(b.id) from accounts a, subaccounts b;
> ^C
> CANCEL request sent
> ERROR:  Query was cancelled.
> actmgr=> select count(id) from accounts;
> count
> -----
>   781
> (1 row)
>
> actmgr=> select count(id) from subaccounts;
> count
> -----
>  1939
> (1 row)
>
> i had to cancel the first one after about a minute, but the second two
> came right back
>
> since
>
> actmgr=> select count(distinct a.id), count(distinct b.id) from accounts a, subaccounts b;
>
> this doesn't work.
>
> -duck
>
> On Thu, 15 Jun 2000, NRonayette wrote:
>
> > Hi everybody,
> > i try something that could work (i tested it on a Oracle base, and it
> > works fine, sorry, i haven't got postgresql at my office :-((
> >
> > select count(distinct (<Primary_key_of_friends>)), count(distinct
> > (<Primary_key_of_strangers>))
> > from Friends, Strangers
> > WHERE friends.f_id = strangers.s_id AND friends.categorie = 1;
> >
> > If f_id and S_id are the primary key of each table, replace
> > <primary_key_of_friend> and <primary_key_of_strangers> by f_id and s_id
> > respectively.
> >
> > i hope this will work for you
> >
> > Nicolas
> >
> > Patrick Coulombe wrote:
> > >
> > > > Try simply SELECT * from friends;
> > > ???
> > > Not working... I just want to know if it's possible to know how many rows
> > > the query return for each table when i do a query with two table ie: select
> > > * from table1, table2 where...
> > >
> > > can i know the number of row for table1 and the number of row for table2
> > > without do 2 querys.
> > >
> > > thank you
> > > hope to be more clear this time
> > > patrick
> > >
> > > > On Tue, 13 Jun 2000, Patrick Coulombe wrote:
> > > >
> > > > > hi,
> > > > > here's the question : if I do this query on my database :
> > > > >
> > > > > SELECT * from friends, strangers WHERE friends.f_id = strangers.s_id AND
> > > > > friends.categorie = 1
> > > > > ----------
> > > > > 88 rows
> > > > >
> > > > > and I need to do this query to know how many rows just for my table
> > > friends
> > > > > (not both table) :
> > > > >
> > > > > SELECT * from friends WHERE friends.f_id = strangers.s_id AND
> > > > > friends.categorie = 1
> > > > > ----------
> > > > > 80 rows
> > > > >
> > > > >
> > > > > Can I just do 1 query and be able to find the number of row for each
> > > tables?
> > > > > Hope to be understand...
> > > > >
> > > > > Patrick
> >
>
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