title: What's the purpose of varchar(0)
body: <p>I recently encountered a problem caused by a typo in the database creation script, whereby a column in the database was created as <code>varchar(0)</code> instead of <code>varchar(20)</code>.</p>
  
  <p>I expected that I would have gotten an error for 0-length string field, but I didn't.  What is the purpose of <code>varchar(0)</code> or <code>char(0)</code> as I wouldn't be able to store any data in this column anyway.</p>