title: SQL - Calculate percentage on count(column)
body: <p>I have the following piece of code which counts how many times something appears in the event column. </p>
  
  <pre><code>SELECT event, count(event) as event_count   
  FROM event_information
  group by event
  
  event   event_count
  a       34
  b       256
  c       45
  d       117
  e       3
  </code></pre>
  
  <p>I want to be able to calculate the percentage of each of the rows like so.</p>
  
  <pre><code>event   event_count event_percent
  a       34          7.47
  b       256         56.26
  c       45          9.89
  d       117         25.71
  e       3           0.66
  </code></pre>