title: postgres '1 year' equals '360 days'?
body: <p>Am wondering if anyone else has encountered this or knows information about it. </p>
  
  <p>Today is November 3, 2014 and if i check whether or not November 5, 2013 is within the last year i get different answers depending on how i check: 1 year versus 365 days</p>
  
  <pre><code>select now() - '20131105' as diff, 
  case when now() - '20131105' &lt;= '1 year' then 'within year' else 'not within year' end as yr_check,
  case when now() - '20131105' &lt;= '365 days' then 'within 365 days' else 'not within 365 days' end as day_check
  
  2014-11-03 16:27:38.39669-06;  363 days 16:27:38.39669;  not within year;  within 365 days
  </code></pre>
  
  <p>Looks like when querying against November 9 tho, it's ok</p>
  
  <pre><code>select now() as right_now, now() - '20131109' as diff, 
  case when now() - '20131109' &lt;= '1 year' then 'within year' else 'not within year' end as yr_check,
  case when now() - '20131109' &lt;= '365 days' then 'within 365 days' else 'not within 365 days' end as day_check
  
  2014-11-03 16:31:12.464469-06;  359 days 16:31:12.464469;  within year;  within 365 days
  </code></pre>
  
  <p>anyone have an idea about this? or is there something about date arithmetic that's funny?</p>
  
  <p>postgres version is 9.2.4</p>