Problem with the following code. (Yes, I'm a beginner)

public static List<Brand> GetBrandsViaSupplier(int supplier)
 {
     var sqlConn = ConnectionFactory.CreateConnection();
     var getBrandsViaSupplier = new SqlCommand(
         "SELECT tblBrands.fldId, tblBrands.fldDescription " +
         "FROM tblBrands " +
         "INNER JOIN tblSupplierData ON tblBrands.fldId = tblSupplierData.fldBrandSystem " +
         "WHERE (tblSupplierData.fldSupplierId = @supplierId) " +
         "GROUP BY tblBrands.fldId, tblBrands.fldDescription " +
         "ORDER BY tblBrands.fldDescription", sqlConn);

     getBrandsViaSupplier.Parameters.AddWithValue("@supplier", supplier);
     var brands = new List<Brand>();
     sqlConn.Open();

     var reader = getBrandsViaSupplier.ExecuteReader();
     if (reader.HasRows)
     {
         while (reader.Read())
         {
             var brand = new Brand();
             brand.BrandId = reader[0].ToString();
             brand.BrandDescription = reader[1].ToString();
             brands.Add(brand);
         }
     }
     reader.Close();
     sqlConn.Close();

     return brands;
 }