By only doing subqueries you basically created a cartesian join. It displayed a record for every possible permutation of the query.
There is a simple explantion of cartesian (cross joins) here.
http://www.dba-oracle.com/t_garmany_...cross_join.htm
As for the community. It is expected when a question you ask is solved you set the thread to solved.
Reputation points can be given as well by clicking on the link below the user name. I beleive your reputation altering power is determined by your own reputation and number of threads participated in as well as solved, possibly the reason it is encouraged to mark threads solved when complete as well as keeping the site clean.
You can see what you reputation altering power is by looking in your account by clicking on your own link.
Have a good one.