title: Ignore specific set of labels on prometheus query
body: <p>I have a metric with 2 labels. Both labels can have 2 values A or B.</p>
  <p>I'd like to sum all the values and exclude the case when Label1=A and Label2=B.</p>
  <pre><code>sum by (Label1,Label2)(metric{?})
  </code></pre>
  <p>Is it possible ?</p>