There are multiple ways to retrive a random row from a table:
Model.find :first, offset: ( Model.count * rand ).to_i
This is fast and requires no custom SQL. All this does is count number of rows in a table and select one row at some offset while still having the table ordered by primary key.
It uses offset (limit), not ID number, so it chooses n-th found row, not a row with ID equal to n. So if you have IDs like
1, 2, 4, 8 and get 3 at random, this method will take
3rd row, which has
ID = 4.
Another way of doing this is use a randomly generated number (up to the current record count) but would require two queries:
offset = rand(Model.count) rand_record = Model.offset(offset).first
Yet another way of doing the same which is quite fast with smaller to medium datasets is to use
RAND() in MySQL, however it is not recommended to use
RAND() in MySQL and you should atleast add `limit to the query.