title: Adding columns to existing index in Oracle
body: <p>I have a relatively large table (81M rows) and an index on it.</p>
  
  <p>I want to add a column to the existing index. </p>
  
  <p>I searched for it on Google, but I couldn't find a way for it.</p>
  
  <p>I've read <a href="http://www.club-oracle.com/forums/how-to-modify-index-created-on-table-in-sql-t2737/" rel="noreferrer">somewhere</a> that the only way to add a column to an index is to drop and recreate it.</p>
  
  <p>However, <a href="http://books.google.com.tr/books?id=TGSd3pkMx5IC&amp;pg=PA104&amp;lpg=PA104&amp;dq=add+column+to+existing+index+oracle&amp;source=bl&amp;ots=9lXackd7bi&amp;sig=DhxN4QNmxBSxzGSwjF9RI2eBuqo&amp;hl=tr&amp;ei=6tbbTsODEtDKtAbMmJnDCw&amp;sa=X&amp;oi=book_result&amp;ct=result&amp;resnum=9&amp;ved=0CFkQ6AEwCDgo#v=onepage&amp;q=add%20column%20to%20existing%20index%20oracle&amp;f=false" rel="noreferrer">here it says</a> it's common practice to add columns to existing index. (Although the author doesn't recommend it.)</p>
  
  <p>So, is it possible to add columns to existing index and if possible is it good practice?</p>