title: Prometheus calculate delta and ignoring one label
body: <p><strong>First some data description:</strong></p>
  
  <p>Name of the metric: query_seconds_count</p>
  
  <p>example value: </p>
  
  <pre><code>query_seconds_count{correlation_id="someUUID",instance="someIp:Port",job="someJob",query_type="query",segment="overall"}
  </code></pre>
  
  <p><strong>What I want to do:</strong></p>
  
  <pre><code>delta(query_seconds_count[1m])
  </code></pre>
  
  <p><strong>The problem:</strong></p>
  
  <p>The label <code>correlation_id</code> is unique for each query and therefore there is no chance to find a matching correlation id for calculating the delta. Delta is therefore always 0.
  Is there any way to ignore the label <code>correlation_id</code> when calculating the delta?</p>
  
  <p>I read about the keywords <code>ignoring</code>, <code>without</code>and <code>by</code>but it seems that they are not applicable to the delta function.</p>
  
  <p><strong>possible workaround</strong></p>
  
  <p>I could workaround the delta function using this but this doesn't look very elegant.</p>
  
  <pre><code>sum(query_seconds_count) without (correlation_id) - sum(query_seconds_count offset 1m) without (correlation_id)
  </code></pre>