title: How to change the type of a column from varchar(30) to varcahar(100)?
body: <p>I have a table that describes like this:</p>
  
  <pre><code>mysql&gt; describe easy_table;
  +---------------------+--------------+------+-----+---------+----------------+
  | Field               | Type         | Null | Key | Default | Extra          |
  +---------------------+--------------+------+-----+---------+----------------+
  | id                  | bigint(20)   | NO   | PRI | NULL    | auto_increment |
  | version             | bigint(20)   | NO   |     | NULL    |                |
  | account_id          | bigint(20)   | NO   | MUL | NULL    |                |
  | city                | varchar(30)  | NO   |     | NULL    |                |
  ...
  | name                | varchar(255) | YES  |     | NULL    |                |
  | name_two            | varchar(255) | YES  |     | NULL    |                |
  +---------------------+--------------+------+-----+---------+----------------+
  13 rows in set (0.03 sec)
  </code></pre>
  
  <p>I'm trying to make the city varchar bigger to varchar(100) and this line doesn't work</p>
  
  <pre><code>alter table easy_table alter column city varchar(100);
  </code></pre>
  
  <p>this also doesn't work</p>
  
  <pre><code>alter table easy_table alter column city varchar(100) not null;
  </code></pre>
  
  <p>I get this error:</p>
  
  <blockquote>
    <p>ERROR 1064 (42000): You have an error in your SQL syntax; check the
    manual that corresponds to your MySQL server version for the right
    syntax to use near 'varchar(100)' at line 1</p>
  </blockquote>