On a more serious note,
A query is a simple spitting out of all the data, based on the fields you have selected, So if atleast one field has a valid value, and "Personnel Number" is one such field, you will get an output in the report.
What you will have to do is to assign certain key fields as selection fields as well as output fields, when designing the Ad-Hoc query.
Then use selection criteria to get out only the results you want, for example Absence Type = Annual Leave( don't want to type the abbreviation here), date range of BEGDA - 01.01.2014 - 30.04.2014, for example. Using Employment Status as a Selection field but not an Output field can help with ensuring inactive employees (i.e people with default positions) are not selected.
I often find that in any case, one always has to download the query output into Excel and do some final manipulations using filters and pivots etc.
Also, play around with the Key Date field, in the query design screen - see what happens if you use "Today" rather than a wider date range.
Hope this helps.