数据库 随机 提取 N条记录

snowing11812

随机取出n条记录：

mysql:
    Select * From tablename order By rand() Limit n
SqlServer:
    select top n * from tablename order by newid()
Access:
    Select top n * FROM tablename orDER BY Rnd(id)
Oracle：
    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
DB2:
    Select * from tablename order by rand() fetch first n rows only