Re: Getting a random row
| От | Thom Brown |
|---|---|
| Тема | Re: Getting a random row |
| Дата | |
| Msg-id | bddc86150910132358g7f1af750qb90ab0d396c22f5c@mail.gmail.com обсуждение исходный текст |
| Ответ на | Re: Getting a random row (Scott Marlowe <scott.marlowe@gmail.com>) |
| Ответы |
Re: Getting a random row
|
| Список | pgsql-performance |
2009/10/14 Scott Marlowe <scott.marlowe@gmail.com>: > > If what you're trying to do is emulate a real world app which randomly > grabs rows, then you want to setup something ahead of time that has a > pseudo random order and not rely on using anything like order by > random() limit 1 or anything like that. Easiest way is to do > something like: > > select id into randomizer from maintable order by random(); > > then use a cursor to fetch from the table to get "random" rows from > the real table. > > Why not just do something like: SELECT thisfield, thatfield FROM my_table WHERE thisfield IS NOT NULL ORDER BY RANDOM() LIMIT 1; Thom
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