If you have a Splunk query that returns empty fields, you can use this query to programatically remove these blanks.

foreach * [  
  | eval maybe<<FIELD>>=<<FIELD>>  
  | fields - <<FIELD>>  
  | rename maybe<<FIELD>> as <<FIELD>>  
]  

Happy Splunking!

note: after I created this macro, I realized I could reuse it to remove identical fields which you might also find useful.