title: Updating a column twice in the same query
body: <p>I want to know what this query will do:</p>
  
  <pre><code>UPDATE users SET
  PaymentAmount = PaymentAmount + TempPaymentAmount,
  PaymentDuration = PaymentDuration + TempPaymentDuration,
  TempPaymentAmount = NULL,
  TempPaymentDuration = NULL
  WHERE UserID = 1234
  </code></pre>
  
  <p>You'll notice that I am trying to copy a value from temp column to the original column and nullify it at the same time. I am wondering if the query will do what I expect.</p>