Обсуждение: About sorting rows randomly
Hi all It's possible to return rows randomly sorted? Something like this: Select * from table order by random Thanks -- Marc Soler
On Fri, 2003-03-28 at 00:32, Marc Soler wrote: > It's possible to return rows randomly sorted? > Something like this: > Select * from table order by random The way I've accomplished this in the past is to create an extra column, call it "randNum," populate it with random numbers, then order by that column. If you don't care how strong the "randomness" is, you can sort by an arbitrary column that has a lot of variation, say a foreign key column ID. I've also seen the logic moved into the application: select the values into an array, and randomly traverse the array. -- Tim Ellis Senior Database Architect and author, tedia2sql (http://tedia2sql.tigris.org) If this helped you, http://svcs.affero.net/rm.php?r=philovivero
H, Is there a simple way to know how many request per second (average) my PG database is currently handling ?? thank you ! jean-arthur silve Jean-Arthur Silve EuroVox 4, Place Félix Eboué 75583 Paris Cedex 12 T : +33 1 44670505 F : +33 1 44670519
Marc Soler writes: > It's possible to return rows randomly sorted? select * from table order by random(); -- Peter Eisentraut peter_e@gmx.net
Don't remember what I wrote this for, but IIRC it outputs the current transaction counter every 1 sec, which you can then use to determine the number of transactions per second. #!/bin/bash while true do sleep 1; psql -U postgres mydb -c "SELECT age(datfrozenxid) FROM pg_database where datname='mydb'"; done; I'm sure you can use this to come up with something more robust. Robert Treat On Fri, 2003-03-28 at 05:39, jeanarthur@eurovox.fr wrote: > H, > > Is there a simple way to know how many request per second > (average) my PG database is currently handling ?? > > thank you ! > > jean-arthur silve
On Friday 28 March 2003 09:32, Marc Soler wrote: > Hi all > > It's possible to return rows randomly sorted? > > Something like this: > > Select * from table order by random SELECT foo, bar, random() AS rand FROM my_table ORDER BY rand Ian Barwick barwick@gmx.net