title: Merge two SQL queries in the same resultset
body: <p>I need to execute this four queries and report the results in a single table. </p>
  
  <pre><code>Q1: select openedDays as crit  from issues_summary where severity="CRITICAL" 
  Q1: select openedDays as maj  from issues_summary where severity="MAJOR" 
  Q1: select openedDays as blocker  from issues_summary where severity="BLOCKER" 
  Q1: select openedDays as minor  from issues_summary where severity="MINOR" 
  </code></pre>
  
  <p>The result of each query is one single column as example: </p>
  
  <pre><code>CRIT
  11
  23
  35
  54
  34
  </code></pre>
  
  <p>Is it possible to run all the queries together to get this result? </p>
  
  <pre><code>BLOCK | CRIT | MAJ | MIN
  11    | 23   | 13  | 17
  23    | 45   | 34  | 33
  ...
  </code></pre>