怎么把上面查询到的teamno，matename根据team表不同的teamno放入matename

 public List<team> getteamdata()
        {
            List<team> tm = new List<team>();
            string sql = "select * from team";
            //string sql2 = "select matename=stuff((select ','+username from student where student.teamno=team.teamno for xml path('')), 1, 1, '')from team group by teamno";
            var reader = SqlDBHelper.ExecuteReader(sql);

            while (reader.Read())
            {
                team tem = new team();
                tem.Teamno = Convert.ToInt32(reader["teamno"]); ;
                tem.Teamname = Convert.ToString(reader["teamname"]);                
                tem.Leadername = Convert.ToInt32(reader["teamleader"]);
                tem.Teammate = Convert.ToInt32(reader["matename"]);
                tem.Keti = Convert.ToString(reader["title"]);
                tem.Zhaiyao = Convert.ToString(reader["digest"]);

                tm.Add(tem);
            }
            return tm;
        }

怎么把上面查询到的teamno，matename根据team表不同的teamno放入matename

https://jingyan.baidu.com/article/363872ec3367226e4ba16f03.html