title: Joining 2 SQL SELECT result sets into one
body: <p>I've got 2 select statements, returning data like this:</p>
  
  <pre><code>Select 1
  col_a   col_b
  
  Select 2
  col_a   col_c
  </code></pre>
  
  <p>If I do union, I get something like</p>
  
  <pre><code>col_a col_b
  </code></pre>
  
  <p>And rows joined. What i need is getting it like this:</p>
  
  <pre><code>col_a  col_b  col_c
  </code></pre>
  
  <p>Joined on data in <code>col_a</code></p>