Re: selecting random row
От | Daniel Lundin |
---|---|
Тема | Re: selecting random row |
Дата | |
Msg-id | 20020402075030.GA4022@shire обсуждение исходный текст |
Ответ на | selecting random row (Heiko Klein <Heiko.Klein@met.no>) |
Список | pgsql-general |
On tis, apr 02, 2002 at 06:57:21 +0000, Heiko Klein wrote: > Hi, > > out of a table i.e. people: > id last first sex age address > select id, random() from people order by 2 limit 1 ; The problem is that the entire table has to be sorted for each select. If it's not very big, is suppose it's OK and better than your solution below. > I would like to select a random id. Id's are a sequence, but some > peoble have been deleted, so there are several id-holes in the > table. > > Furthermore, I would like to specify the random person, like > > select 'random person id' from table where age > 60 and sex = 'm'; > > > > Right now (in perl), I select the complete list of id's into a @list, do > a $id = $list[rand(@list)] and have the right row. But this seems to be > very time-consuming, and I would like to have it done completely in the > Pg-database. > > Regards, > > Heiko > > ---------------------------(end of broadcast)--------------------------- > TIP 1: subscribe and unsubscribe commands go to majordomo@postgresql.org >
В списке pgsql-general по дате отправления: