From: roopa perumalraja <roopabenzer@yahoo.com>
To: pgsql-sql@postgresql.org, Richard Broersma Jr <rabroersma@yahoo.com>
Subject: Re: Add calculated fields from one table to other table
Date: Mon, 30 Oct 2006 22:54:18 -0800 (PST)
Message-ID: <20061031065418.10959.qmail@web50802.mail.yahoo.com> (raw)
In-Reply-To: <610212.14371.qm@web31803.mail.mud.yahoo.com>
Hi Richard,
Thanks for your help. That does make sense, but I am not able to get the result what I wanted exactly. Let me explain you.
I have ticks table in which I have columns like ric, tick_time, price & volume. The times table has just one column with times_time which has time data for each minute ie.)
Ticks
ric | tick_time | price | volume
A | 12:00:01 | 23.00 | 12
A | 12:00:02 | 26.00 | 7
B | 12: 00:02 | 8.00 | 2
B | 12:01:01 | 45.00 | 6
Times
times_time
12:00
12:01
12:02
Now I want the timeseries for each minute for all ric in the tick table. So my query goes like this for a particular ric say for example ric 'A'
select foo.ric, tm.times_time, count(tk.*), avg(tk.price), sum (tk.price*tk.volume)/sum(tk.volume), sum(tk.volume) from (select ric from ticks where ric = 'A' group by ric) as foo, times tm left join ticks tk on tk.tick_time >= tm.times_time and tk.tick_time < (tm.times_time + '1 minute' :: interval)::time and tk.ric = 'A' group by tm.times_time, foo.ric order by tm.times_time;
I get the result as I expect, but i am not able to derive a query for all rics in the tick table.
I really appreciate your help.
Regards
Roopa
Richard Broersma Jr <rabroersma@yahoo.com> wrote:
> select foo.ric, tm.times_time, count(tk.*), avg(tk.price),
> sum(tk.price*tk.volume)/sum(tk.volume), sum(tk.volume) from (select distinct ric from ticks) as
> foo, times tm left join ticks tk on tk.tick_time >= tm.times_time and tk.tick_time <
> (tm.times_time + '1 minute' :: interval)::time and tk.ric = foo.ric group by tm.times_time,
> foo.ric order by tm.times_time;
>
> I get a error message like this:
>
> ERROR: invalid reference to FROM-clause entry for table "foo"
> HINT: There is an entry for table "foo", but it cannot be referenced from this part of the
> query.
>
> Can you help me with this?
I will try, but to start with, to help us, when you have a difficult query to solve, you should
simplify your query as much a possible. This way we can more quickly see what you are intending
verses the problem you are having.
1 tip: (select distinct ric from ticks)
I think that you will find that:
(select ric from ticks group by ric)
is much faster than using the distinct.
The error in the query that I see is that you are using foo as a criteria in the ON syntax. This
will not work. To illistrate:
A,B join C
ON (B.id = C.id) --ON syntax only works with joins
AND (B.id2 < C.id) --The And is still part of the ON syntax
--you can not reference A since it is not joined
Where
A.id = B.id --you can only specify a non-joined tables contrainst
AND
A.id2 < C.id2
; --in the where clause
I hope this helps.
Regards,
Richard Broersma JR.
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To: pgsql-sql@postgresql.org
Cc: roopabenzer@yahoo.com, rabroersma@yahoo.com
Subject: Re: Add calculated fields from one table to other table
In-Reply-To: <20061031065418.10959.qmail@web50802.mail.yahoo.com>
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