title: Spark distinct by multiple column and condition is or
body: <p>datafram1 like this:</p>
  <pre><code>id    no    name
  1     101    aaa
  2     102    bbb
  3     103    ccc
  </code></pre>
  <p>datafram2 like this:</p>
  <pre><code>id    no    name
  4     101    aaa
  2     106    bbb
  7     107    ccc
  </code></pre>
  <p>I want to distinct by id or no, so I want to result dataframe like this
  result dataframe:</p>
  <pre><code>id    no    name
  3     103    ccc
  7     107    ccc
  </code></pre>
  <p>How to get this result by scala spark</p>