Обсуждение: 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...
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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.
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@yahoo.co.in> Sent by: pgsql-novice-owner@postgresql.org 12/13/2007 04:47 AM |
|
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.