some problem, but I find the solution, this is :
2 February Feb 28 (29 in leap years)
this is my code
public string GetCountArchiveByMonth(int iii)
{
// iii: is number of months, use any number other than (**2**)
con.Open();
SqlCommand cmd10 = con.CreateCommand();
cmd10.CommandType = CommandType.Text;
cmd10.CommandText = "select count(id_post) from posts where dateadded between CONVERT(VARCHAR, @start, 103) and CONVERT(VARCHAR, @end, 103)";
cmd10.Parameters.AddWithValue("@start", "" + iii + "/01/2019");
cmd10.Parameters.AddWithValue("@end", "" + iii + "/30/2019");
string result = cmd10.ExecuteScalar().ToString();
con.Close();
return result;
}
now for test
lbl1.Text = GetCountArchiveByMonth(**7**).ToString(); // here use any number other than (**2**)
**
because of check
**February**is maxed 28 days,
**