title: A way to only select rows that indicate progression, and ignore rows that indicate recovery?
body: <p>I have a dataset with thousands of patients that include their ID and their disease stage over time. The data is complicated because there are patients that get worse, then recover, then get worse again. I would like to only select rows from a patient that indicate disease progression. </p>
  
  <p>For example, ID 1 progresses from 3 > 4, then recovers back to stage 1 before worsening again to stage 5. How can I ignore rows that indicate recovery, and only keep rows that indicate progression over time? Is this even possible using SQL? Thank you in advance!</p>
  
  <p><strong>What data looks like:</strong></p>
  
  <pre><code>ID   stage_date  disease_stage
  1    1-JAN-15         3
  1    3-JAN-15         4
  1    6-JAN-15         1
  1    9-JAN-15         5
  1    10-JAN-15        1
  </code></pre>
  
  <p><strong>What I want:</strong></p>
  
  <pre><code>ID   stage_date  disease_stage
  1    1-JAN-15         3
  1    3-JAN-15         4
  1    9-JAN-15         5
  </code></pre>