为什么我只得到一个字段而不是所有表与DataSet和DataAdapter（使用ODBC）

Question

    dynamic table;
    DataSet dataSet = new DataSet();
    //String conString = “Driver={Adaptive Server Enterprise};server=ipAddress;port=portNumber;db=databaseName;uid=strUserName;pwd=strPassword”;
    string connectionString = "DSN=ASE_DB;Uid=dbs;Pwd=dbssql";
    string queryString = "select DISTINCT mission_type,count(distinct mission_id) as num from missions.dbo.DECODE_MISSIONS having count(distinct mission_id)>20";
    using (OdbcConnection connection =  new OdbcConnection(connectionString))
    {
        OdbcDataAdapter adapter = new OdbcDataAdapter(queryString, connection);

        // Open the connection and fill the DataSet.
        try
        {
            connection.Open();
            table= adapter.Fill(dataSet, "missions");