quick selection of a random row from a large table in mysql

Question

What is a fast way to select a random row from a large mysql table?

I\'m working in php, but I\'m interested in any solution even if it\'s in another language.

Answer 1

Take a look at this link by Jan Kneschke or this SO answer as they both discuss the same question. The SO answer goes over various options also and has some good suggestions depending on your needs. Jan goes over all the various options and the performance characteristics of each. He ends up with the following for the most optimized method by which to do this within a MySQL select:

SELECT name
  FROM random AS r1 JOIN
       (SELECT (RAND() *
                     (SELECT MAX(id)
                        FROM random)) AS id)
        AS r2
 WHERE r1.id >= r2.id
 ORDER BY r1.id ASC
 LIMIT 1;

HTH,

-Dipin