title: What is the 'expression' in COUNTAX and COUNTX (DAX)?
body: <p>The documentation for COUNTAX (DAX) and COUNTX (DAX)
  states that the second argument is an expression that is evaluated for each row.</p>
  
  <p>See: <a href="https://docs.microsoft.com/en-us/dax/countax-function-dax" rel="nofollow noreferrer">https://docs.microsoft.com/en-us/dax/countax-function-dax</a></p>
  
  <p>This is exactly what I need, but I cannot figure out what the 'expression'  should look like.</p>
  
  <p>The example given in Microsoft's documentation is this:</p>
  
  <pre><code>=COUNTAX(FILTER('Reseller',[Status]="Active"),[Phone])
  </code></pre>
  
  <p>But the second argument (<code>[Phone]</code>) does not look like an expression.
  An expression in my expectation is something like <code>"value &gt; 3 AND value &lt;= 10"</code></p>
  
  <p>What kind of expression can be used here? </p>