title: Add computed column to temporary table Oracle
body: <p>I want to add a computed column to a global temporary table in Oracle.
  For the simple tables the request works well.</p>
  
  <pre><code>alter table ma_table add ma_column as (column1*column2);
  </code></pre>
  
  <p>But for the temporary ones it refuses the use of <code>as</code>.
  Is there a way to add a new computed column to the temporary table in Oracle?</p>