Mysql 随机获取N条数据

MySQL

SELECT * FROM T_USER ORDER BY RAND() LIMIT 10;

ORACLE

SELECT * FROM (SELECT * FROM T_USER ORDER BY DBMS_RANDOM.RANDOM()) WHERE RONUM <= 10;

SQL Server

SELECT TOP 10 * FROM T_USER ORDER BY NEWID();

Access

SELECT TOP 10 * FROM T_USER ORDER BY rnd([一个自动编号字段])

这条语句在 Access 中的“查询”中是可以运行并得到随机结果的，但在 ASP.NET等后台程序代码中却无法得到预期的随机效果。

以ASP.NET为例,正确的写法如下

Random random = new Random(System.Guid.NewGuid().GetHashCode());
int r = random.Next();
string sql = "SELECT TOP 10 * FROM T_USER ORDER BY RND(" + (-r) + "*自动编号字段)"