Problem with DataSet

Hi all,
I got a problem with my dataset.  As you can see in my code below,  I need to return dataset at the end of this section.
But i found that, the dataset returned was empty. I try to debug each row of my code, i found that if i select "Table", the dataset is empty, but if i choose "Table1", it will return what i want. Anyone can help me on this?
private DataSet RetrieveData() { string sql = @"select * from schoolRecord "; //Declare a data set to store the query information DataSet ds = new DataSet(); //Initialize the SqlConnection object using (SqlConnection myConnection = new SqlConnection(ConnString)) { //Open an SQL connection myConnection.Open(); //Initialize the SqlCommand object using (SqlCommand lCmd = new SqlCommand(sql, myConnection)) { ...