[1]普通方法, 效率太低
SELECT * FROM table ORDER BY rand() LIMIT 10;
[2] JOIN的方法:
SELECT *
FROM `table` AS t1 JOIN (SELECT ROUND(RAND() * ((SELECT MAX(id) FROM `table`) - (SELECT MIN(id) FROM `table`)) + (SELECT MIN(id) FROM `table`)) AS id) AS t2
WHERE t1.id >= t2.id
ORDER BY t1.id LIMIT 10;