treeview与数据库连接问题
 protected void Page_Load(object sender, EventArgs e)
        {
            if (!IsPostBack)
            {
                string connstr = ConfigurationManager.ConnectionStrings["SportsShoop"].ConnectionString;
                string sql = "select e.typeName,d.sportsName,d.typeID,d.sportsID from SportsType e,SportsInfo d where e.typeID = d.typeID";
                SqlDataAdapter adp = new SqlDataAdapter(sql,connstr);
                DataSet ds = new DataSet();
                adp.Fill(ds);
                DataView dv = ds.Tables[0].DefaultView;
                dv.RowFilter = "parentId=0";               
foreach(DataRowView drv in dv)
                {
                    TreeNode root = new TreeNode(drv.Row["typeName"].ToString(), drv.Row["typeID"].ToString());
                    this.TreeView1.Nodes.Add(root);
                }
                for (int i = 0; i < this.TreeView1.Nodes.Count; i++)
                {
                    this.AddChildNode(ds, this.TreeView1.Nodes[i]);
                }
            }
        }
我的数据库表中没有parentId，联合查询之后的表，dv.RowFilter = "parentId=0"; 这段怎么写？