Hope this code may help you . If you want to get only one Table format from Data Base means you can use like this ,If you want to fetch multiple Table means you can use DataSet
but for your prob DataTable is enough .
string x=textBox1.Text;
string y=textBox1.Text;
DateTime fro=Convert.ToDateTime (x);
DateTime to=Convert.ToDateTime (y);
SqlConnection con = new SqlConnection(@"Data Source=.\Ahmed;Initial Catalog=Market;Integrated Security=True");
con.open();
string SqlQuery=string.Format("SELECT dat ,product_id FROM product where dat between '"+fro+"' and '"+to+"' ");
SqlDataAdapter adp = new SqlDataAdapter(SqlQuery,con);
DataTable tab=new DataTable();
adp.Fill(tab);
con.close();
Hope it may help you.....