title: Create a Google Analytics view filter that excludes hits with missing fields
body: <p>I have a mobile iOS app that uses Google Analytics.</p>
  
  <p>Recently I have been receiving hits in my reports that are clearly not coming from my app. I guess someone must be using my tracker ID (I hope, by mistake).</p>
  
  <p>So I've been trying to create a filtered view that doesn't include this traffic. My first approach was to create an include filter on the applicationID field, hoping that would filter out any hit that doesn't have the right applicationID. When using the Google Analytics iOS SDK, this field is always set with the app bundle identifier, so it is highly improbable - if not impossible - that a hit sent by mistake by someone else will have the correct value.</p>
  
  <p>It didn't work, and after wondering why for days, I just found out. The document about view filters (<a href="https://support.google.com/analytics/answer/1033162" rel="nofollow">https://support.google.com/analytics/answer/1033162</a>) actually says : "<em>Fields specified in a filter must exist in the hit and not be null in order for the filter to be applied to that hit</em>". So I can't have filters on missing fields, which is a problem because those unwanted hits I'm receiving seems to have all of their fields empty.</p>
  
  <p>Which leads me to ask : Has anyone ever had this problem before ? And if yes, what is your approach ?</p>
  
  <p>Currently I am using an unfiltered view with a custom segment that does the work (because the filtering of empty fields is doable using segments). But I would like to have a filtered view on which I could apply <em>real</em> segments.</p>
  
  <p>Thanks for your insights</p>