Two Datatables from one dataset for single rdlc using asp.net ,c#

Question

Im creating payslip report using rdlc file in c#, asp.net. Im populating values from two tables for a single rdlc file. In My Dataset1.xsd file, i have to two tables as salary and employee. Im getting informations from both table and adding it to report. I followed below table but all values in report shows as

Error

When i populating one table then it works fine. What im doing wrong? If the below code is wrong method,please guide me. For previous projects , i used rdlc.But multiple datasets for multiple tables.

protected void GetPayslipReport(string employeename)
{
    ReportViewer1.ProcessingMode = ProcessingMode.Local;
    ReportViewer1.LocalReport.ReportPath = Server.MapPath("~/Payslip.rdlc");
    ReportViewer1.LocalReport.DataSources.Clear();

    int Empid = 0;
    string sQuery;
    sQuery = "SELECT * FROM salary WHERE (EmployeeName ='" + employeename + "'AND month='" + UserMonthList.SelectedItem.ToString() + "'AND Year ='" + UserYearList.SelectedItem.ToString() + "')";

    MySqlDataAdapter ada = new MySqlDataAdapter(sQuery, GlobalCS.objMyCon);
    DataSet ds = new DataSet();
    ada.Fill(ds);      

    ReportDataSource reportDataSource = new ReportDataSource();
    reportDataSource.Name = "DataSet1_salary";
    reportDataSource.Value = ds.Tables[0];
    ReportViewer1.LocalReport.DataSources.Add(reportDataSource);

        /*To get EmpID */
         sQuery = "SELECT EmpID FROM employee WHERE (EmployeeName ='" + employeename + "')";            
         MySqlCommand command = new MySqlCommand(sQuery, GlobalCS.objMyCon);
         MySqlDataReader reader = command.ExecuteReader();
         while (reader.Read())
          {
              Empid =  reader.GetInt32("EmpID");                 
          }
         reader.Close();
        /***/

    sQuery = "SELECT * FROM employee WHERE EmpID =" + Empid;
    MySqlDataAdapter ada2 = new MySqlDataAdapter(sQuery, GlobalCS.objMyCon);
    DataSet ds2 = new DataSet();
    ada2.Fill(ds2);

    ReportDataSource reportDataSource2 = new ReportDataSource();
    reportDataSource2.Name = "DataSet1_employee";
    reportDataSource2.Value = ds2.Tables[0];
    ReportViewer1.LocalReport.DataSources.Add(reportDataSource2);           
    
}