IErrorInfo.GetDescription - SELECT查询不起作用

Question

我正在为MS Access使用以下SQL语句：

Public Function GetSectionID(ByVal Course As String, ByVal YrLvl As Integer, ByVal Section As String) As Integer
    If Connection.State = ConnectionState.Closed Then
        Connection.Open()
    End If

    Dim sql As String = "SELECT SectionID FROM tblCourses WHERE Course = '" & Course & "' AND (YrLevel = " & YrLvl & " AND Section = '" & Section & "')"
    Dim comd As New OleDbCommand(sql, Connection)
    Dim reader As OleDbDataReader = comd.ExecuteReader

    Dim int As Integer = -1

    If reader.HasRows Then
        While reader.Read
            int = CInt(reader.Item(0))
            Exit While
        End While
    End If
    Return int
End Function

当我执行程序时，它返回错误：

  

IErrorInfo.GetDescription因E_FAIL（0x80004005）而失败。

可能出了什么问题？