title: SSAS Tabular: Append two tables with a different number of columns
body: <p>I'd like to ´UNION´ or ´Append´ two tables in SSAS with certain overlapping Column names, and some differences as well, which changes over time.</p>
  <pre><code>TableA:
  | ColA | ColB | ColC | ColD |
  |------|------|------|------|
  | 1    | 1    | 0    | 1    |
  | 0    | 1    | 1    | 1    |
  
  TableB:
  | ColA | ColB | ColE |
  |------|------|------|
  | 1    | 1    | 0    |
  | 0    | 1    | 1    |
  
  Expected Result:
  | ColA | ColB | ColC | ColD | ColE |
  |------|------|------|------|------|
  | 1    | 1    | 0    | 1    |      |
  | 0    | 1    | 1    | 1    |      |
  | 1    | 1    |      |      | 0    |
  | 0    | 1    |      |      | 1    |
  </code></pre>
  <p>Is there an option in SSAS to make this happen?</p>
  <p>Kind regards,
  Igor</p>