title: PostgreSQL Subtract exactly a year from a date field PSQL
body: <p>I tried to do <a href="https://stackoverflow.com/questions/4247060/sql-subtract-exactly-a-year">SQL Subtract exactly a year</a> but the syntax in PSQL didn't work.  In my case dates were imported with 2 digit years so they all have birthdays off by 1900 years.</p>
  
  <pre><code>UPDATE patients SET birthday = dateadd(year, 100, getdate(birthday)
  </code></pre>
  
  <p>throws:</p>
  
  <pre><code>ERROR:  syntax error at or near "table"
  LINE 1: UPDATE table SET datefield = DATE_ADD(datefield, INTERVAL 1 ...
  </code></pre>