How can I best write a query that selects 10 rows randomly from a total of 600k?
I think here is a simple and yet faster way, I tested it on the live server in comparison with a few above answer and it was faster.
SELECT * FROM `table_name` WHERE id >= (SELECT FLOOR( MAX(id) * RAND()) FROM `table_name` ) ORDER BY id LIMIT 30;
//Took 0.0014secs against a table of 130 rows
SELECT * FROM `table_name` WHERE 1 ORDER BY RAND() LIMIT 30
//Took 0.0042secs against a table of 130 rows
SELECT name
FROM random AS r1 JOIN
(SELECT CEIL(RAND() *
(SELECT MAX(id)
FROM random)) AS id)
AS r2
WHERE r1.id >= r2.id
ORDER BY r1.id ASC
LIMIT 30
//Took 0.0040secs against a table of 130 rows