Because it won't be uniformly random. If the random ordering is: A B C D E F G H I J K L M and I want to select 5 random records, I'll always get similarly grouped records (i.e. I'll never get A and M in the same query).
On Jul 9, 1:42 pm, Barry Hunter <barrybhun...@googlemail.com> wrote: > Why cant you do "> rand ORDER BY asc LIMIT 5" ??? > > Yes you will get consecutive records, but as the random number you > meant to have stored is random, the records are not consecutive in > reality (only in the index). > > You might even find it not that much more expensive (but benchmark on > live!) to say retreive 10 record and discard a random selection of 5, > for even more randomness, but seems kinda pointless. > > On 09/07/2009, aloo <aleem.maw...@gmail.com> wrote: > > > > > > > > > Hi all, > > > I'm trying to write a GQL query that returns N random records of a > > specific kind. My current implementation works but requires N calls to > > the datastore. I'd like to make it 1 call to the datastore if > > possible. > > > I currently assign a random number to every kind that I put into the > > datastore. When I query for a random record I generate another random > > number and query for records > rand ORDER BY asc LIMIT 1. > > > This works, however, it only returns 1 record so I need to do N > > queries. Any ideas on how to make this one query? Thanks. > > -- > Barry > > -www.nearby.org.uk-www.geograph.org.uk- --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Google App Engine" group. To post to this group, send email to google-appengine@googlegroups.com To unsubscribe from this group, send email to google-appengine+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en -~----------~----~----~----~------~----~------~--~---
