Пожалуйста объясните ошибку моего запроса

        private void btnOk2_Click(object sender, EventArgs e)
        {
            string query = $"SELECT teachers.ID_teacher, teachers.fio " +
                $"FROM teachers LEFT JOIN (SELECT [lectures for gr/te].teachers.ID_teacher, [lectures for gr/te].fio, [lectures for gr/te].date " +
                $"FROM [lectures for gr/te] " +
                $"WHERE(([lectures for gr/te].date) Between {dateTimePicker3.Value.ToShortDateString()} AND {dateTimePicker2.Value.ToShortDateString()})) zaprosnagruzka ON teachers.ID_teacher = zaprosnagruzka.ID_teacher " +
                $"WHERE(((zaprosnagruzka.date) Is Null))";
            OleDbCommand command = new OleDbCommand(query, dbConnection);
            MessageBox.Show(query);
            command.ExecuteNonQuery();
            this.freeTeachersTableAdapter.Fill(this.instituteDataSet.freeTeachers);
        }

string query = $"SELECT teachers.ID_teacher, teachers.fio " +
                $"FROM teachers LEFT JOIN (SELECT [lectures for gr/te].teachers.ID_teacher, [lectures for gr/te].fio, [lectures for gr/te].date " +
                $"FROM [lectures for gr/te] " +
                $"WHERE(([lectures for gr/te].date) Between #{dateTimePicker3.Value.ToString("yyyy.MM.d")}# AND #{dateTimePicker2.Value.ToString("yyyy.MM.d")}#)) zaprosnagruzka ON teachers.ID_teacher = zaprosnagruzka.ID_teacher " +
                $"WHERE(((zaprosnagruzka.date) Is Null))";

private void btnOk2_Click(object sender, EventArgs e)
{
    const string query = @"SELECT
    l.teachers.ID_teacher,
    l.fio
FROM
    [lectures FOR gr/te] AS l
WHERE
    l.date BETWEEN ? AND ?";
    OleDbCommand command = new OleDbCommand(query, dbConnection);
    command.Parameters.Add(new OleDbParameter("dateFrom", OleDbType.Date)).Value = dateTimePicker3.Value.Date;
    command.Parameters.Add(new OleDbParameter("dateTo", OleDbType.Date)).Value = dateTimePicker2.Value.Date;
    command.ExecuteNonQuery();
    this.freeTeachersTableAdapter.Fill(this.instituteDataSet.freeTeachers);
}