title: Addition with NULL values
body: <p>In a stored procedure (Oracle in my case), I want to add some values to an existing record. Problem is that both the existing value and the value to be added can be null. I only want the result to be NULL when both operands are null. If only one of them is null, I want the result to be the other operand. If both are non-null, I want the result to be "normal" addition.</p>
  
  <p>Here's what I am using so far:</p>
  
  <pre><code>SELECT column INTO anz_old FROM aTable Where &lt;someKeyCondition&gt;;
  IF anz_old IS NULL
  THEN
      anz_new := panzahl;
  ELSE
      anz_new := anz_new + NVL (panzahl, 0);
  END IF;
  UPATE aTabel set column = anz_new Where &lt;someKeyCondition&gt;;
  </code></pre>
  
  <p>Is there a more elegant way (pereferably completely in SQL, i.e. just in an update statement short of a long CASE-Statement with basically the same logic as the above code)?</p>