How to QUERY perform operation and then UPDATE on entire table : <p>I have a large table with around 10 million rows.  I need to take numbers from 2 columns perform some function and then save the result into a 3rd column.</p>

<p>Is there an efficient way of doing this?  The only way I have been able to do this is to QUERY and save the result into a tuple.  Then in a second for loop iterate through the tuple where the result and unique hash is stored and filter by hash and then update.  </p>

<p>This is very very very slow though!  Is there a better way to do this?</p>
