Hi there, I'm kind of new to joining two tables.  Please bear with me
with this simple example.  I have three tables.

Guests is a list of guests that are coming to the party.  The primary
key of this table is 'id' and the foreign key that ties the guests to
the registered user of the site is 'user_id'.

Invites is a list of inviations sent out, with a primary key of 'id'
and a foreign key of 'guest_id' that ties it in with the guest that
the invite was sent to.

Gifts is like invites, but is a list of gifts that have been received
by the guest. Primary key is 'id' and the foreign key is once again
'guest_id'.

Now, if I want to run a query that pulls all of the gifts that belong
to any guests that in turn belong to the registered user, I would do
something like:

SELECT firstname,lastname,guests.id,giftname,giftdate FROM
guests,gifts WHERE (guests.id = invites.guest_id) AND (guests.user_id
= '$user_id')

$user_id is our session variable.

Ok that's fine, it gives me all of the guests first names and last
names and the name of the gifts and dates they were received, but only
of the guests that the registered user is "owner" of, ie guests that
belong to that user.

*** MY PROBLEM  *****

What kind of query would I run if I want to delete a gift that belongs
to the registered user?  Currently, the only way to determine if a
gift belongs to the registered user is to first see if the gift came
from a guest that belongs to the registered user.  It's what I refer
to as the once-removed table.  I need to make a binary comparison in a
situation where there are three separate tables, instead of just two. 
I know this is beginner stuff, and I hope I'm articulating my problem
without being too confusing(!) but I really want to get a grasp on
this, and none of the books I have read have specific enough examples
to guide me.

I am trying to envision something like:

DELETE FROM gifts WHERE guests.user_id = '$user_id' AND guests.id =
gifts.guest_id AND gift.id = '2'

Of course I get an error.  Do I need to start with "DELETE FROM
gifts,guests..." but then how will it know that I'm only actually
deleting from gifts??

Thank you so much in advance,
B

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