Allocated Pen Query

[thpus2]

I need to create a query which will show what pens on todays date do not have a bookings in them.
The two tables i would need to use are:
Booking

1. Booking_number (which is the primary key)
2. Pen_number (which is the foreign key)
3. start_date
4. end_date

Pen

1. Pen_number (primary key)
2. Block_number(which is the foreign key)

I know i need to use the date() function and is null but my query at present is in Sql
SELECT Pen.pen_no, Booking.start_date, Booking.end_date
FROM Pen LEFT JOIN Booking ON Pen.pen_no = Booking.pen_no
GROUP BY Pen.pen_no, Booking.start_date, Booking.end_date
HAVING (((Booking.start_date)<Date()) AND ((Booking.end_date)<Date())) OR (((Booking.start_date)>Date()) AND ((Booking.end_date)>Date())) OR (((Booking.start_date) Is Null) AND ((Booking.end_date) Is Null));

This works but it displays the same pen again if it has had more then one booking in it. How do i make so that i can produce a report that will have just the pens that are free once?
Thanx
Thpus

 

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SELECT DISTINCT Pen.pen_no, Booking.start_date, Booking.end_date
FROM Pen LEFT JOIN Booking ON Pen.pen_no = Booking.pen_no
GROUP BY Pen.pen_no, Booking.start_date, Booking.end_date
HAVING (((Booking.start_date)<Date()) AND ((Booking.end_date)<Date())) OR (((Booking.start_date)>Date()) AND ((Booking.end_date)>Date())) OR (((Booking.start_date) Is Null) AND ((Booking.end_date) Is Null));

 

[thpus2]

Even with SELECT DISTINCT the query displays all the times that pen has been booked in.
Very strange.
Thanx
Thpus

 

[___]

Are all the times different?

 

[thpus2]

Some timespans overlap but most don't.
But the query repeats everyrecord that pen has been used.
So that i do get all the unallocated pens but like pen 4 repeats 4 times. So in report this does not look right.
Thanx
Thpus