title: Error while creating unique index in Oracle: ORA-01452
body: <p>I had a compound unique index in my table, but due to business reasons, I had to take one of the columns out of the index. So I dropped the index. Now, with the reduced number of columns, it throws error while creating the index: ORA-01452: cannot CREATE UNIQUE INDEX; duplicate keys found.</p>
  
  <p>Previously the index had an additional column and everything was working fine.</p>
  
  <pre><code>CREATE UNIQUE INDEX MGRRS.ITRCHESS ON MGRRS.TTRCHESS (MHYSTU, MAJUSDESK, DATSNAQ, TIMESSDG)  TABLESPACE IMGRRS  LOCAL
                                              *
  ERROR at line 1:
  ORA-01452: cannot CREATE UNIQUE INDEX; duplicate keys found
  </code></pre>
  
  <p>Note 1: Please note that I have not dropped the column from the table.</p>