Julio1974 , Welcome to Bytes!
This would be something best handled in an aggregate or cross-tab query. And then there is the crosstab query that should be able to handle the same thing. In this case you're preference.
You should post your entire SQL - Please format it using the code button and you should read the posting guidlines as to how to post the SQL.
You might consider reading thru
Aggregate Query Woes as some of the pitfalls are pointed out here.
Here's Mr. Brown's site... a ton of tips so I'd bookmark this site! However, in this case the cross-tab:
Crosstab query techniques
Some basic SQL stuff - :
Queries in Access using SQL View
Another mention of the cross-tab; however, this will help with some with the report side:
Dynamic Reports
That should be enough to get you started. Rabbit, Neopa, and/or others should be along shortly (if they haven't already posted while I was typing this ... they type faster than I do :-P )
Once you get your query/report put together, should you still be having issues, please read the FAQ and posting guidelines about how to post your SQL/Code and will take another poke at the problem.