title: COUNT DISTINCT values from multiple tables in Power BI
body: <p>I need a measure that counts the distinct serial numbers from multiple tables;</p>
  
  <pre><code>Serial#
  A
  B
  A
  B
  C
  </code></pre>
  
  <pre><code>Serial#
  A
  D
  C
  D
  C
  </code></pre>
  
  <pre><code>B
  C
  D
  A
  </code></pre>
  
  <p>I need my measure to be 4. There are 4 distinct Serial Numbers</p>
  
  <p>I know how to make a table with the distinct values but I can't seem to create a measure that skips the step of creating an entirely new table. here is what I have tried:</p>
  
  <pre><code>COUNT(DISTINCT(UNION(VALUES(LABOR_HOURS[Serial #]),VALUES(OIL_SAMPLES[Serial#]), VALUES(UTILIZATION[SerialNumber]))))
  </code></pre>
  
  <p>thanks in advance for the help.</p>