在mysql中通過sql語句獲取隨機數據的方式如下, 經測試,在1000W數據的表中,執行速度在10多毫秒
SELECT * FROM user1 AS t1 JOIN (SELECT ROUND(RAND() * ((SELECT MAX(id) FROM user1) – (SELECT MIN(id) FROM user1)) + (SELECT MIN(id) FROM user1)) AS id) AS t2 WHERE t1.id >= t2.id ORDER BY t1.id LIMIT 10;
另外一種(參考MySql 是怎樣運行的 從根上理解Mysql)
mysql> select count(*) into @C from t; 獲取表的數據條數
set @Y1 = floor(@C * rand()); 獲取隨機數
set @Y2 = floor(@C * rand()); 獲取隨機數
set @Y3 = floor(@C * rand()); 獲取隨機數
select * from t limit @Y1,1; //在應用代碼裏面取Y1、Y2、Y3值,拼出SQL後執行
select * from t limit @Y2,1;
select * from t limit @Y3,1;
參考: https://www.douban.com/note/331011058/