title: Select Query with IN clause - having duplicate values in IN clause
body: <p>I have a query as below,</p>
  
  <pre><code>SELECT count(*) from Employee where e_id IN (121, 234, 536, 234).
  </code></pre>
  
  <p>In above query, <code>234</code> is repeated twice.</p>
  
  <p>But the above query returns result with <code>count = 3</code> instead of 4.</p>
  
  <p><strong>My Question is how duplicate data gets filtered in Select query when i have not used <code>DISTINCT</code>.</strong></p>
  
  <p>or <strong>how does database treats IN clause</strong>, is it sort of <code>List</code>(duplicate values) or <code>Set</code>(unique values) or neither.</p>