title: Add leading zeros to mySQL column
body: <p>I've tried several solutions for this, but none seem to work. I have a zip code column thats <code>INT(10)</code>.</p>
  
  <p>I need to convert it (to a VARCHAR, I guess) so that zip codes with a leading zero can be stored. Now they are "8721" instead of "08721".</p>
  
  <p>I tried this:</p>
  
  <pre><code>SELECT RIGHT('0000'+ CONVERT(VARCHAR,zip_code),5) AS NUM FROM p23data;
  </code></pre>
  
  <p>but I get an error:</p>
  
  <p><code>check the manual that corresponds to your MySQL server version for the right syntax to use near 'VARCHAR,zip_code),5) AS NUM FROM p23data' at line 1</code></p>
  
  <p>I think the above is to create a new column, but I just need to update my existing <code>zip_code</code> column.</p>
  
  <p>What am I not doing right here?</p>