On Mon, Oct 09, 2006 at 05:02:07PM -0700, Bricklen Anderson wrote: > Fourat Zouari wrote: > >Hello all, > >Any one could suggest the best way to copy data from table to table in > >the same db, the reason why am seeking for this is that the first table > >is becoming very big, and old data has no reason why to stay there, so i > >created a cloned table but without indexes and constraints (lighter) and > >now i would like to copy 'some' data from first to second table (copied > >data is data older than 3 months, i have a timestamp column). > > > >In other way, i have a table called 'hotqueues' where i store fresh > >messages queued, once messages are treated, they stay in 'hotqueues' but > >with a flag indicating that their arent queued for treatment.. > >so in this way, data will rest there forever, slowing down any searches > >in that table, the solution was to copy old messages to another table > >called 'coldqueues' that has the same structure as 'hotqueues' but > >lighter (without constraints and indexes). > >How to copy these data with 100% data-loose free. > > > >Thanks for any help you can provide. > > If you just want to copy the data across to the other table: > begin; > insert into table2 select * from table1 where <some criteria>; > commit; > > if you also want to remove that same data from table1: > begin; > insert into table2 select * from table1 where <some criteria>; > delete from table1 where <same criteria as above>; > commit; You need to be careful with this method. For what the OP wants to do it would probably work, but not always. The problem is that in some scenarios, <same criteria as above> won't necessarily return the same set of rows. Starting in 8.2 you'll be able to do something like INSERT INTO table2 DELET FROM table1 WHERE ... RETURNING *; The RETURNING * will return all the data that the command deleted. In older versions, your best bet is to store the data you're moving in a temporary table, and then use that to delete the exact rows. -- Jim Nasby jim@xxxxxxxxx EnterpriseDB http://enterprisedb.com 512.569.9461 (cell)
