数据库 随机 提取 N条记录
随机取出n条记录：

mysql:

    Select * From tablename order By rand() Limit n 

    select top n * from tablename order by newid()

    Select top n * FROM tablename orDER BY Rnd(id)

    Select * from (select * from tablename order by sys_guid()) where rownum < n    Select * from (select * from tablename order by dbms_random.value) where rownum < n

    Select * from tablename order by rand() fetch first n rows only