MySql随机取数据

[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;

评论

2 楼 jayliu 2009-12-11  

第二种方式速度挺快，可惜有一个瑕疵，就是不能够保证每次都取得足够的想要数据

1 楼 xiao_xiong_2009 2009-12-11  

好办法