This is more of a SQL question than a Crystal question, but I'll give it a shot.
Where on database query produces right results...
If there is a query that is giving the correct results when run in a query tool like Toad, use that query.
You could also use sub-queries in your From clause. The format might look something like this:
Select
<fields, calculations...>
from
(Select <fields>
from Fact1
inner join Dimensions on ...
where ...) as qry1
full outer join
(Select <fields>
from Fact1
inner join Dimensions on...
where ...) as qry2 on ...
where ....