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 1;这里面都涉及到了主键id，请问如果表里面没有主键如何随机取一条数据？用
$data=M('info')->order('rand()')->limit(1)->select();速度很慢，要2-3秒 最佳答案
