mysql隨機獲取n條記錄

之前很多次遇到類似問題，每次都得去搜，還是整理一下吧。

主要解決，隨機獲取n條數據庫中記錄。

SELECT *
FROM `table` AS t1 JOIN (SELECT ROUND(RAND() * ((SELECT MAX(uid) FROM `table`)-(SELECT MIN(uid) FROM `table`))+(SELECT MIN(uid) FROM `table`)) AS uid) AS t2
WHERE t1.uid >= t2.uid
ORDER BY t1.uid LIMIT 30




總數據量是36,493的情況下，執行時間爲：0.0017