Re: Query with Dynamic tables

From: "Obe, Regina DND\\MIS" <robe(dot)dnd(at)cityofboston(dot)gov>
To: 'solarsail' <solarsail(at)gmail(dot)com>, "'pgsql-novice(at)postgresql(dot)org'" <pgsql-novice(at)postgresql(dot)org>
Subject: Re: Query with Dynamic tables
Date: 2005-10-04 20:28:59
Message-ID: 35F9812087218F47B050D41D1B58298B086F69@dnd5.dnd.boston.cob
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You could try using table inheritance. For example you would create a table
called

Mytable and have all your other tables inherit from it. Something along the
form

CREATE TABLE mytable
(
myfield1 int4,
myfield2
)

CREATE TABLE mytable001
(
)
INHERITS (mytable)

And so on

When you want to insert then you insert into mytable00x

When you want to query all the tables then you do

SELECT myfield1, myfield2
FROM mytable

-----Original Message-----
From: solarsail [mailto:solarsail(at)gmail(dot)com]
Sent: Tuesday, October 04, 2005 3:18 PM
To: pgsql-novice(at)postgresql(dot)org
Subject: [NOVICE] Query with Dynamic tables

[ i posted this originally to the pgsql-sql list, sorry for cross posting ]

I have a large number of tables with a common naming convention

mytable001, mytable002, mytable003 ... mytable00n

I would like to do a query across all of the tables, however I do not know
all of the tables before hand, and I do not want to ( cant ) manually
generate a query like

select * from mytable001, mytable002, mytable003

I have a query that returns the names of the tables I want to query:

select tablename from pg_tables where tablename like 'mytable%'

We use the table as a logging repository. It can get very large 250
000+ records. Because of the large number of records that we have in
the table we found it was much faster to perform inserts on a smaller table.
Our current system rolls the tables over every 12 hours or so, creating a
new table with the following behavior:

CREATE TABLE mytable_temp {...}

ALTER TABLE mytable RENAME TO mytable_NNN;
ALTER TABLE mytable_temp RENAME TO mytable;

I want to join the mytable_NNN tables together in order to perform queries
against my huge set of data to generate some reports. I'm probably going to
create a temporary table with a few indexes to make the reports run
faster... however I need to join the tables all together first.

I know this is possible, because i've done it with postgresql before!

Thanks

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