sharepoint full text query with attributes missing isn't returning the results I expected

Question

If I am doing a search in sharepoint, some of the results I'm expecting are not being returned. I believe its because in active directory these entries may not have all the fields. So a name that doesn't have the givenName attribute set in active directory is not being returned from this query. Is there a way I can get this to work like I expected?

"select LastName, FirstName, PreferredName, AccountName from scope() where \"scope\"='People' AND (LastName like '%" + search + "%' OR FirstName like '%" + search + "%' OR PreferredName like '%" + search + "%')";