title: Is the 'as' keyword required in Oracle to define an alias?
body: <p>Is the 'AS' keyword required in Oracle to define an alias name for a column in a SELECT statement? </p>
  
  <p>I noticed that </p>
  
  <pre><code>SELECT column_name AS "alias"
  </code></pre>
  
  <p>is the same as</p>
  
  <pre><code>SELECT column_name "alias"
  </code></pre>
  
  <p>I am wondering what the consequences are of defining a column alias in the latter way. </p>