select();    $result = M("admin")->where("id>2")->select();    $result = M("admin")->where("id>2")->order("id desc")->limit("0,5")->field("id,username,psssword")->select();    $result = M("admin")->where("id>2")->group("messageId")->having("messageId > 3")->order("id desc")->limit("0,5")->field("id,username,psssword")->select();    //查询一条记录，返回一维数组    $result = M("admin")->find();    $result = M("admin")->where("id=2")->find();    //要处理的数据放在数组data中    $data   = array(            "username" => 'wang',            "password" => "123456"        );    //添加记录，返回影响行数    $updateRowNum = M("admin")->add($data);    //删除记录，返回影响行数    $updateRowNum = M("admin")->where("id = 2")->delete();    //修改数据放在新数组new_data中    $new_data   = array(            "username" => 'wang_new',            "password" => "123456_new"        );    //修改记录，返回影响行数    $updateRowNum = M("admin")->where("id = 2")->save($new_data);        //执行select语句(不管是多行还是一行，全部返回二维数组)    $result = M()->query("select * from admin a,user u where a.id = user.aid");    //执行insert、update、delete语句，返回受影响行数    $updateRowNum = M()->execute("insert/update/delete语句");    //计算查询行数(一般用于select语句)    $row    = M("admin")->select()->count();    $row    = M("admin")->where("id > 3")->select()->count();?>