ruby - Rails 3: Get Random Record

Question

So, I've found several examples for finding a random record in Rails 2 -- the preferred method seems to be:

Thing.find :first, :offset => rand(Thing.count)

Being something of a newbie I'm not sure how this could be constructed using the new find syntax in Rails 3.

So, what's the "Rails 3 Way" to find a random record?

Answer 1

Thing.first(:order => "RANDOM()") # For MySQL :order => "RAND()", - thanx, @DanSingerman
# Rails 3
Thing.order("RANDOM()").first

or

Thing.first(:offset => rand(Thing.count))
# Rails 3
Thing.offset(rand(Thing.count)).first

Actually, in Rails 3 all examples will work. But using order RANDOM is quite slow for big tables but more sql-style

UPD. You can use the following trick on an indexed column (PostgreSQL syntax):

select * 
from my_table 
where id >= trunc(
  random() * (select max(id) from my_table) + 1
) 
order by id 
limit 1;