title: How to define a tags / value query in Grafana 7.4?
body: <p>I am having some trouble understanding <a href="https://grafana.com/docs/grafana/latest/variables/variable-value-tags/" rel="nofollow noreferrer">the concept of Value groups/tags in Grafana</a> 7.4.x with MySQL as a data source.</p>
  <p>My main query gets the Countries</p>
  <pre><code>SELECT 
      NAME as __text, 
      id AS __value 
  from 
      countries
  </code></pre>
  <p>The tags query gets the Continents</p>
  <pre><code>SELECT 
      NAME as __text, 
      id AS __value 
  from 
      continents
  </code></pre>
  <p>That works so far, tags are shown in the list, but nothing happens once I click on them.</p>
  <p>My tags query:</p>
  <pre><code>continents.$tag.*
  </code></pre>
  <p>The tags query seems to be the problem. Any help is greatly appreciated.</p>