title: INSERT INTO subtract 2 values
body: <p>Is it possible for an INSERT query to subtract 2 values you have entered to create a 3rd value that can then be inserted into a table - if that makes sense...</p>
  
  <p>e.g.</p>
  
  <pre><code>INSERT INTO table1 (column1, column2, column3)
  VALUES ('50', '25', column1 - column2)
  </code></pre>