title: Cannot drop a column in PostgreSQL
body: <p>I am pretty new in PostgreSQL and only know basic operations about database. I have a database called neuro_db with username neuro_user. Now I found I cannot delete a column in a table from neuro_db.</p>
  
  <p>After I tried <code>psql neuro_db</code> in ubuntu 14.04, I got in a command line started with <code>neuro_db=#</code>. The <code>\d</code> command would show a table like this:</p>
  
  <pre><code>                         List of relations
   Schema |               Name                |   Type   |   Owner
  --------+-----------------------------------+----------+------------
   public | auth_group                        | table    | neuro_user
   public | auth_group_id_seq                 | sequence | neuro_user
   public | auth_group_permissions            | table    | neuro_user
   public | auth_group_permissions_id_seq     | sequence | neuro_user
   public | auth_permission                   | table    | neuro_user
   public | auth_permission_id_seq            | sequence | neuro_user
   public | auth_user                         | table    | neuro_user
   public | auth_user_groups                  | table    | neuro_user
   public | auth_user_groups_id_seq           | sequence | neuro_user
   public | auth_user_id_seq                  | sequence | neuro_user
   public | auth_user_user_permissions        | table    | neuro_user
   public | auth_user_user_permissions_id_seq | sequence | neuro_user
   public | django_admin_log                  | table    | neuro_user
   public | django_admin_log_id_seq           | sequence | neuro_user
   public | django_content_type               | table    | neuro_user
   public | django_content_type_id_seq        | sequence | neuro_user
   public | django_migrations                 | table    | neuro_user
   public | django_migrations_id_seq          | sequence | neuro_user
   public | django_session                    | table    | neuro_user
   public | neuro_category                    | table    | neuro_user
   public | neuro_category_id_seq             | sequence | neuro_user
   public | neuro_page                        | table    | neuro_user
   public | neuro_page_id_seq                 | sequence | neuro_user
  (23 rows)
  </code></pre>
  
  <p>I wanted to edit the table "neuro_page" and after typing <code>\d neuro_page
  </code>, it will show this table:</p>
  
  <pre><code>                                   Table "public.neuro_page"
     Column    |          Type          |                        Modifiers
  -------------+------------------------+---------------------------------------------------------
   id          | integer                | not null default      nextval('neuro_page_id_seq'::regclass)
   category_id | integer                | not null
   title       | character varying(128) | not null
   text        | text                   | not null
   url         | character varying(200) | not null
   photo       | character varying(100) | not null
   order       | character varying(128) | not null
   date        | date                   | not null
   views       | integer                | not null
   likes       | integer                | not null
  </code></pre>
  
  <p>I wanted to delete the "order" column in this table so I tried typed <code>ALTER TABLE neuro_page DROP COLUMN order</code> right after the <code>neuro_db=#</code> line, but nothing happened. There was also nothing after trying <code>ALTER TABLE neuro_page</code> and <code>DROP COLUMN order</code> respectively. The "order" column is still there! And no error information!</p>
  
  <p>I have also searched on google for the answer but found nothing. I think I have followed the normal operations in database but can not drop a single column in a table. There is no foreign key for "order" column.</p>
  
  <p>I'd be very greatful if anyone can help me with this issue. Thanks!</p>