พี่ๆคะ ช่วยดูโค้ดการจองเวลาให้หน่อยค่ะ เป็นโปรเจคจบ ด่วนมากๆเลยค่ะ

Function checkTime(ByVal teacherID As String, ByVal bookDate As String, ByVal bookTime As String) As DataSet
        Dim ds As New DataSet
        Dim sql As String = "select teacher_id,convert(varchar(10),appointment_date,120) as Date,appointment_time from Appointment,teacher where teacher_id ='" & teacherID & "' and convert(varchar(10),appointment_date,120) ='" & bookDate & "' and appointment_time ='" & bookTime & "'"
        Dim da As New SqlDataAdapter(sql, cnn)
        da.Fill(ds, "checkTime")
        Return ds
    End Function

Protected Sub cmdSave_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles cmdSave.Click
        Dim ds As New DataSet
        Dim check As String
        check = Right(Str(Val(Format(CalendarPopup1.SelectedDate, "yyyy")) - 543), 2) & Format(CalendarPopup1.SelectedDate, "-MM-dd")
        ds = selectData.checkTime(ddlTeachername.SelectedValue, check, TimePicker1.PostedTime.ToString)
        
        Dim runID As Integer
        runID = insertData.runID("Appointment", "Appointment_ID")
        hidApp_ID.Value = runID


        If ds.Tables(0).Rows.Count = 0 Then
            hidApp_ID.Value = runID
            insertData.insertAppointment(lblStudent_ID.Text, lblStudent_Name.Text, ddlTeachername.SelectedValue, hidApp_ID.Value, txtTitle.Text, CalendarPopup1.SelectedDate, TimePicker1.PostedTime.ToString, txtContent.Text)
            ScriptManager.RegisterStartupScript(Page, Page.GetType(), "", "alert('" + "บันทึกข้อมูลเรียบร้อยแล้ว" + "');", True)
            Response.Redirect("showAppointment2.aspx")
            txtTitle.Text = ""
            txtContent.Text = ""
        Else
            ScriptManager.RegisterStartupScript(Page, Page.GetType(), "", "alert('" + "กรุณาจองเวลาการนัดพบใหม่" + "');", True)
        End If

    End Sub