title: How to calculate 90th Percentile, SD, Mean for data in SQL
body: <p>Hi I have a table facility. Which holds a score for each day (Multiple scores can be reported each day and both would be valid)</p>
  
  <p>I need to calculate the 90th percentile, SD, and Mean for score by month.</p>
  
  <p>Facility:</p>
  
  <pre><code>Id   Month Date  score
  1    Jan     1    5
  1    Jan     1    5
  1    Jan     2    3
  1    Jan     3    4
  1    Jan     4    4
  1    Jan     5    4
  1    Feb     1    5
  1    Feb     1    5
  1    Feb     2    3
  1    Feb     3    4
  1    Feb     4    4
  1    Feb     5    4
  </code></pre>
  
  <p>Is there any way?</p>
  
  <p>Thanks for your help.</p>