SQL Server-- SELECT TOP 50 * FROM TAB_USERS ORDER BY NEWID(); ORACLE-- SELECT * FROM (SELECT * FROM TAB_USERS ORDER BY DBMS_RANDOM.RANDOM()) WHERE RONUM=50 MYSQL-- SELECT * FROM TAB_USERS ORDER BY RAND() LIMIT 50 { ACCESS-- SELECT TOP 50
sql server--> select top 50 * from tab_users order by newid();
ORACLE--> SELECT * FROM (SELECT * FROM TAB_USERS ORDER BY DBMS_RANDOM.RANDOM()) WHERE RONUM
MYSQL--> SELECT * FROM TAB_USERS ORDER BY RAND() LIMIT 50
{
ACCESS--> SELECT TOP 50 * FROM TAB_USERS ORDER BY RND([字段])
这条语句在ACCESS中的查询结果是正确的，但在ASP.NET等后台代码要写成如下：
1 系统使用三层构架2 数据库访问使用sqlHelper3 编辑器使用FreeTextBox4 布局采用Div+Css5 正则表达式实现数据验证6 动态构建sql查询语句
Random random=new Random(System.Guid.NewGuid().GetHashCode());
int val=random.Next();
string sql="SELECT TOP 50 * FROM TAB_USERS ORDER BY RND("+(-r)+"字段)";
