Checking for empty set -- Oracle

Hi -

I'm having a little bit of a problem.
When the page loads a query is ran and populates the fields depending on the user name.
Sometimes it seems like the query doesn't even run.

I want to check to see if it is an empty set,
Then lblEmptySet.Text = "Empty"

Here is my code:

string mySelectQuery = "SELECT EMPLOYEE_NUMBER,START_DATE FROM BMDW_EMPLOYEE WHERE LAST_NAME ='" + lblLastName.Text.ToUpper() + "'";
                    string myConnString = "data source=*****;user id=******; password=******";
                    OracleConnection myDBConnection = new OracleConnection(myConnString);

                    OracleDataAdapter myAdapter = new OracleDataAdapter(mySelectQuery, myDBConnection);
                    myDBConnection.Open();
                    OracleDataReader myReader = myAdapter.SelectCommand.ExecuteReader();
                   
                    while (myReader.Read())
                    {
                        string EmpID = myReader["EMPLOYEE_NUMBER"].ToString();
                        lblEmpNum.Text = EmpID;

                        string strHireDate = myReader["START_DATE"].ToString();
                        txtHireDate.Text = strHireDate;
                    }

                    myDBConnection.Close();