title: SQL - Insert one column to another, without merging data
body: <p>Searching the threads I could only find combining or merging, but not inserting and keeping original values.
  So here is what I have:</p>
  
  <pre><code>ID time1 time2 time3
  1   20    NULL  30
  2   50    NULL  NULL
  2   20    30    40
  </code></pre>
  
  <p>What I need is:</p>
  
  <pre><code>ID time
  1   20
  1   30
  2   50
  2   20
  2   30
  2   40
  </code></pre>
  
  <p>While ignoring Nulls.
  Thanks!</p>