How to request a random row in SQL?

Question

How can I request a random row (or as close to truly random as is possible) in pure SQL?

Answer 1

I have to agree with CD-MaN: Using "ORDER BY RAND()" will work nicely for small tables or when you do your SELECT only a few times.

I also use the "num_value >= RAND() * ..." technique, and if I really want to have random results I have a special "random" column in the table that I update once a day or so. That single UPDATE run will take some time (especially because you'll have to have an index on that column), but it's much faster than creating random numbers for every row each time the select is run.