On Thu, Sep 22, 2011 at 5:32 AM, Rohan Malhotra <yourbuddyrohan@xxxxxxxxx> wrote: > Hi Gurus, > What is difference between > select * from items order by random() limit 5; > and > select * items limit 5; > my basic requirement is to get random rows from a table, my where clause > will make sure I won't get same rows in repeated execution of above queries. The biggest problem with the order by random() limit 5 is the cost. If there's 1,000 or so rows, no big deal, if there's 10,000,000 rows it's gonna be slow... -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
