How to draw a name in a database [duplicate]

Question

I have names in my database and I want to draw a name for a contest.

Anyone have an idea for that ?

Thanks !!

Answer 1

SELECT * FROM table WHERE num_value >= RAND() * (SELECT MAX(num_value) FROM table) LIMIT 1

This works in constant time, regardless of the table size, if num_value is indexed. One caveat: this assumes that num_value is equally distributed in the range 0..MAX(num_value). If your dataset strongly deviates from this assumption, you will get skewed results (some rows will appear more often than others).

Answer 2

A query like this could work

SELECT * FROM `table` WHERE id >= (SELECT FLOOR( MAX(id) * RAND()) FROM `table` ) ORDER BY id LIMIT 1;