mysql 随机查询数据

随机查询数据

1.

SELECT * FROM `table`

WHERE id >= (SELECT floor(RAND() * (SELECT MAX(id) FROM `table`)))

ORDER BY id LIMIT 5;

2.SELECT * FROM `table`

WHERE id >= (SELECT floor( RAND() * ((SELECT MAX(id) FROM `table`)-(SELECT MIN(id) FROM `table`)) + (SELECT MIN(id) FROM `table`)))

ORDER BY id LIMIT 5;

3.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 5;

备注：前两种方法测试没问题，用时很短，效率很高。10多万条数据，0.01s就能搞定。后面一种方法也有很多网友采用，但是我这儿没有执行成功，修修改改依旧不行，放弃了。