How to validate if a column has the same data

Select COUNT (DISTINCT S.WorkQueueID) from crm_Sale S
where SaleID

DataTable1TableAdapter Da = new DataTable1TableAdapter();
                int Gridviewcount = 0;
                bool returnval = false;
                int Count = 0;

                try
                {
                    Gridviewcount = dgrvInfo.RowCount;
                    for (int c = 0; c < Gridviewcount; c++)
                    {
                        WorkQueueId = Convert.ToInt32(dgrvInfo.Rows[c].Cells[11].Value.ToString());
                        Count = Convert.ToInt32(Da.GetData(WorkQueueId));

                        
                    }

                    if (Count < 1)
                    {
                        returnval = true;
                    }

                    else
                    {
                        returnval = false;
                    }

                }


                catch (Exception)
                {
                    returnval = false;

                }
                return returnval;
            }