Error when trying to get dates given a condition from Access database in WPF

Question

I'm developing a WPF application that saves user registers and dates into an Access database. I've had no problems inserting the dates, but now I want to retrieve with a DataReader some dates given a certain condition (e.g., all dates from the current month). When I try to read it through my application, the DataReader returns no rows. But when I try the same query on DBeaver, it does return data.

This reading problem only happens when I try to read dates given a certain condition as I said before, since if I try to read all the dates, there's no issues.

I've tried using a parameterized command and also directly inserting the condition with String.Format().

I currently have this function (which tries to calculate how many days in the month are left if we don't count the days saved in the DB):

public static int CalculateDaysLeftInMonth()
{
    int days = 0;
    List<DateTime> dates = new List<DateTime>();

    try
    {
        if (dbConnection.State != ConnectionState.Open)
            dbConnection.Open();

       OleDbCommand dbCommandQuery = new OleDbCommand {
            CommandText = "SELECT * FROM DatesTable WHERE Date LIKE @Condition"
        }

        dbCommandQuery.Parameters.AddWithValue("@Condition", String.Format("{0:yyyy-MM}-%", DateTime.Now));

        OleDbDataReader dbReader = dbCommandQuery.ExecuteReader();

        if (!dbReader.HasRows)
            return -1;

        while (dbReader.Read())
        {
            dates.Add(new FechaFestivo(dbReader.GetDateTime(0).Date));
        }

        dbConnection.Close();

        DateTime startDate = new DateTime(DateTime.Now.Year, DateTime.Now.Month, 1),
                 endDate = new DateTime(DateTime.Now.Year, DateTime.Now.Month, 
                           DateTime.DaysInMonth(DateTime.Now.Year, DateTime.Now.Month));

        for (DateTime date = startDate; date <= endDate; date = date.AddDays(1))
        {
            if (!dates.Any(ff => ff.Date == date.Date))
            {
                days++;
            }
        }
    }
    catch (OleDbException ex)
    {
        dbConnection.Close();
        return -1;
    }

    return days;
}

This is the parameterized version. I've also tried using:

dbCommandQuery.CommandText = String.Format("SELECT * FROM DatesTable WHERE Date " +
"LIKE '{0:yyyy-MM}-%'", DateTime.Now);

I expect to get a List of dates like this, so I can iterate through them:

(CalendarioLaboral would be DatesTable and FechaFestivo would be Dates)

Thank you in advance.

Answer 1

The code that worked for me in the end is the following one:

public static int CalculateDaysLeftInMonth()
{
    int days = 0;
    List<DateTime> dates = new List<DateTime>();

    try
    {
        if (dbConnection.State != ConnectionState.Open)
            dbConnection.Open();

       OleDbCommand dbCommand = new OleDbCommand {
           CommandText = String.Format("SELECT * FROM {0} WHERE (DATEPART('yyyy', FechaFestivo) = @Year " +
                                       "AND DATEPART ('m', FechaFestivo) = @Month)", TablaCalendario)
       }

       dbCommandQuery.Parameters.AddWithValue("@Year", DateTime.Now.Year);
       dbCommandQuery.Parameters.AddWithValue("@Month", DateTime.Now.Month);

        OleDbDataReader dbReader = dbCommandQuery.ExecuteReader();

        if (!dbReader.HasRows)
            return -1;

        while (dbReader.Read())
        {
            dates.Add(new FechaFestivo(dbReader.GetDateTime(0).Date));
        }

        dbConnection.Close();

        DateTime startDate = new DateTime(DateTime.Now.Year, DateTime.Now.Month, 1),
                 endDate = new DateTime(DateTime.Now.Year, DateTime.Now.Month, 
                           DateTime.DaysInMonth(DateTime.Now.Year, DateTime.Now.Month));

        for (DateTime date = startDate; date <= endDate; date = date.AddDays(1))
        {
            if (!dates.Any(ff => ff.Date == date.Date))
            {
                days++;
            }
        }
    }
    catch (OleDbException ex)
    {
        dbConnection.Close();
        return -1;
    }

    return days;
}

Using the DatePart function as said @Holger and @June7 in the comments. Thank you!