title: DISTINCT clause in SQLite
body: <p>Recently i found that SQLite don't support <code>DISTINCT ON()</code> clause that seems postgresql-specific. For exeample, if i have table <code>t</code> with columns <code>a</code> and <code>b</code>. And i want to select all items with distinct <code>b</code>. Is the following query the only one and correct way to do so in SQLite?</p>
  
  <pre><code>select * from t where b in (select distinct b from t)
  </code></pre>
  
  <p>Sample data:</p>
  
  <pre><code>a | b
  __|__
  1   5
  2   5
  3   6
  4   6
  </code></pre>
  
  <p>What i expect in return:</p>
  
  <pre><code>a | b
  __|__
  1   5
  3   6
  </code></pre>