title: INSERT when NOT duplicate row?
body: <p>I simply want to replace (update) <code>DATE</code>, <code>PRICE</code> and <code>OLDPRICE</code> when a price is different than the PRICE in my table where <code>MODEL</code> is unique.  </p>
  
  <p>Sample Row Table Data:</p>
  
  <pre><code>DATE        |   MAKE   |   MODEL   |   PRICE   |   OLDPRICE
  2012-04-15  | Advance  | DTA-100-X |   400     |   390
  </code></pre>
  
  <p>There must be a dozen ways to do this but I'm looking for the best solution to use in a MySQL query. </p>
  
  <p>Should I be using:<br/></p>
  
  <ol>
  <li><code>INSERT INTO..ON DUPLICATE KEY UPDATE</code></li>
  <li><code>REPLACE INTO..</code></li>
  <li><code>UPDATE...WHERE PRICE != XXX</code></li>
  </ol>
  
  <p>Essential syntax would be to <code>UPDATE</code> if the <code>MODEL</code> is the same but the <code>PRICE</code> is different; <code>OLDPRICE</code> becomes <code>PRICE</code> on <code>UPDATE</code></p>
  
  <p>*<strong><em>UPDATE</em>*</strong></p>
  
  <p>This REPLACES whether price changed or not.  I only want updates/replaces if price changed ie, this should NOT update anything given above example, however it does because date is different:</p>
  
  <pre><code>REPLACE INTO MyTable (DATE, MAKE, MODEL, PRICE, OLDPRICE) VALUES ('2012-10-02', 'Advance', 'DTA-100-X', '400', '390')
  </code></pre>