title: sql: select where problem with null value
body: <p>students table:</p>
  <pre><code>id          name
  0           NULL
  1           John
  </code></pre>
  <p>Query:</p>
  <pre><code>SELECT * from students WHERE name != &quot;John&quot;;
  </code></pre>
  <p>Expected output:</p>
  <pre><code>0           NULL
  </code></pre>
  <p>With my test, the result is empty, how i can solve this?</p>
  <pre><code>SELECT * from students WHERE name != &quot;John&quot; OR name == NULL;
  </code></pre>
  <p><a href="https://i.stack.imgur.com/SQ5XS.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/SQ5XS.png" alt="screen" /></a></p>