title: Update if different/changed
body: <p>Is it possible to perform an update statement in sql, but only update if the updates are different?</p>
  
  <p>for example</p>
  
  <p>if in the database, <code>col1 = "hello"</code></p>
  
  <pre><code>update table1 set col1 = 'hello'
  </code></pre>
  
  <p><strong>should not</strong> perform any kind of update</p>
  
  <p>however, if</p>
  
  <pre><code>update table1 set col1 = "bye"
  </code></pre>
  
  <p>this <strong>should</strong> perform an update.</p>