title: Postgres alter index vs drop index and create index
body: <p>I have to write a migration command to remove a column from the index. Currently let us say I have <code>table1</code> that  has index on <code>col1 and col2</code></p>
  
  <p>I want to remove <code>col1</code> from the index. I am looking at <a href="https://www.postgresql.org/docs/9.4/static/sql-alterindex.html" rel="nofollow noreferrer">https://www.postgresql.org/docs/9.4/static/sql-alterindex.html</a> but it does not seem I can actually just remove a column?</p>
  
  <p>If yes, will it be better to remove the column and how VS</p>
  
  <ul>
  <li>Create new Index</li>
  <li>Drop the old index</li>
  </ul>
  
  <p>Also, I want to do the reverse if I need to do downgrade. So just wondering how to achieve this</p>