Re: SQL Query

From: Mark Wimer <mwimer(at)usgs(dot)gov>
To: Ashish Karalkar <ashish_postgre(at)yahoo(dot)co(dot)in>
Cc: ashish(dot)karalkar(at)netcore(dot)co(dot)in, pgsql-novice(at)postgresql(dot)org
Subject: Re: SQL Query
Date: 2007-12-13 17:23:39
Message-ID: OF27C227F3.63C28F73-ON852573B0.005F68AC-852573B0.005F8CEF@usgs.gov
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-general pgsql-novice

See if this works; the max aggregate in the subquery could be just about
any function, since it's only going to join to one row.

select max(m1.output_date), m1.parent_id, max(m2.output_id) as
latest_output
from my_table M1 inner join (select output_date, output_id, parent_ID from
my_table) as M2
on m1.output_date = m2.output_date and m1.parent_ID = m2.parent_ID

Where M1.output_date < now()
Group by m1.parent_id

-- Mark

Ashish Karalkar <ashish_postgre(at)yahoo(dot)co(dot)in>
Sent by: pgsql-novice-owner(at)postgresql(dot)org
12/13/2007 04:47 AM

To
pgsql-novice(at)postgresql(dot)org, ashish(dot)karalkar(at)netcore(dot)co(dot)in
cc

Subject
[NOVICE] SQL Query

Hello List member,
I have a table which ha sfollowing structure

my_table:
(
output_id serial priimary key,
parent_id int,
output_date timesatmp
)

parent_table:

(parent_id int,
parent desc
)

the my_table contains data for previous as well as future output dates.
for single parent there may be multiple rows.

I want to retrieve all the output_id which are having latest output_date
but less than now() (no future output_dates) group by parent_id

Thanks in advance

With Regards
Ashish...

Chat on a cool, new interface. No download required. Click here.

In response to

  • SQL Query at 2007-12-13 09:47:36 from Ashish Karalkar

Browse pgsql-general by date

  From Date Subject
Next Message Reg Me Please 2007-12-13 17:36:43 COPY speedup
Previous Message Scott Marlowe 2007-12-13 17:03:18 Re: Need to find out which process is hitting hda

Browse pgsql-novice by date

  From Date Subject
Next Message A. Kretschmer 2007-12-13 20:24:17 Re: remote user
Previous Message Tom Lane 2007-12-13 16:37:30 Re: Is now() atomic?