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ruby-on-railsrandomrails-activerecord

Random record in ActiveRecord

I'm in need of getting a random record from a table via ActiveRecord. I've followed the example from Jamis Buck from 2006.

However, I've also come across another way via a Google search (can't attribute with a link due to new user restrictions):

 rand_id = rand(Model.count)
 rand_record = Model.first(:conditions => ["id >= ?", rand_id])

I'm curious how others on here have done it or if anyone knows what way would be more efficient.

Solution

  • I haven't found an ideal way to do this without at least two queries.

    The following uses a randomly generated number (up to the current record count) as an offset.

    offset = rand(Model.count)

# Rails 4
rand_record = Model.offset(offset).first

# Rails 3
rand_record = Model.first(:offset => offset)

    To be honest, I've just been using ORDER BY RAND() or RANDOM() (depending on the database). It's not a performance issue if you don't have a performance issue.