title: Filter prometheus results by metric value, not by label value
body: <p>Because <a href="https://stackoverflow.com/questions/38783424/prometheus-topk-returns-more-results-than-expected">Prometheus topk returns more results than expected</a>, and because <a href="https://github.com/prometheus/prometheus/issues/586" rel="noreferrer">https://github.com/prometheus/prometheus/issues/586</a> requires client-side processing that has not yet been made available via <a href="https://github.com/grafana/grafana/issues/7664" rel="noreferrer">https://github.com/grafana/grafana/issues/7664</a>, I'm trying to pursue a different near-term work-around to my similar problem.</p>
  
  <p>In my particular case most of the metric values that I want to graph will be zero most of the time. Only when they are above zero are they interesting.</p>
  
  <p>I can find ways to write prometheus queries to filter data points based on the value of a <em>label</em>, but I haven't yet been able to find a way to tell prometheus to return time series data points only if the value of the <em>metric</em> meets a certain condition. In my case, I want to filter for a value greater than zero.</p>
  
  <p>Can I add a condition to a prometheus query that filters data points based on the metric value? If so, where can I find an example of the syntax to do that?</p>