先建立这个函数用来获取datatable
        /// <summary>
        /// 获取数据
        /// </summary>
        /// <param name="SQLcmd">查询的SQL语句</param>
        /// <returns>返回获取后的数据DataTable</returns>
        private DataTable GetTable(string SQLcmd)
        {
            try
            {
                DataTable dt = new DataTable();
//自己修改你本地机器的连接串，其他的不用改
                System.Data.OleDb.OleDbConnection oledbcon = new System.Data.OleDb.OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + Application.StartupPath + "\\" + "Address.xls;Extended Properties=\"Excel 8.0;HDR=Yes;IMEX=1\"");
                oledbcon.Open();
                System.Data.OleDb.OleDbDataAdapter oleda = new System.Data.OleDb.OleDbDataAdapter(SQLcmd,oledbcon);
                DataSet ds = new DataSet();
                oleda.Fill(ds,0,0,"temp");
                dt = ds.Tables[0];
                oledbcon.Close();
                return dt;
            }
            catch(Exception ex)
            {
                throw ex;
            }
        }


再执行以下代码
DataSet ds = new DataSet();
//添加第一个表
ds.Tables.Add(GetTable("SELECT student from 数据库"));
//添加第二个表
ds.Tables.Add(GetTable("SELECT class from 数据库"));

谢谢，谢谢。