title: Postgres query about the roles of each user
body: <p>I'm trying to make a query that shows the users and all the roles that they have.  I already know how to ask about the roles of one particular user:</p>
  
  <pre><code>SELECT oid, rolname FROM pg_roles WHERE
  pg_has_role( 'name_of_user', oid, 'member');
  </code></pre>
  
  <p>Any idea how to do it?</p>