title: Oracle get row where column value changed
body: <p>Say I have a table, something like</p>
  
  <pre><code>ID     CCTR    DATE
  -----  ------  ----------
  1      2C      8/1/2018
  2      2C      7/2/2018
  3      2C      5/4/2017
  4      2B      3/2/2017
  5      2B      1/1/2017
  6      UC      11/23/2016
  </code></pre>
  
  <p>There are other fields, but I made it simple.  So I create a query where i have the date in descending order.  I was to return the row where there was a change in CCTR.  So in this case it would return ID 4.  Basically i want to find the previous value of CCTR before it changed, in this case from 2B to 2C.</p>
  
  <p>How do I do this?  Ive tried to google it, but can't seem to find the right method.</p>