SQL query, SELECT (Count/Count ) ...??

I have a table column containing Registered Users IDs related to tickets
they bought. If the ticket was bought by a non registered user, the value 'na'
is entered.
Now, I need to find the percentage of the Registered Users that bought tickets.

So basically i need to do a divide of the number of Registered users by the number of occurence in this column...

here is what i ve been working on:
(A)

SELECT COUNT(pv1.idabonne)
FROM placevendues pv1
WHERE pv1.idabonne != 'na';
this counts the number of Registered users who bought tickets (Ex.:let s say 30)

(B)

SELECT COUNT(pv1.idabonne)
FROM placevendues pv1 ;
this counts the number of lines in my table (Ex.:let s say 50)

Now.. how can I do some sort of Select A/B*100 so i can have the percentage i want...? which would be 30/50*100 = 60%

Thanks

Louis Gagnon
-Comp. Eng. Student- Received on Fri Mar 14 2003 - 21:20:01 CET