title: Check if specific value exists in mysql column
body: <p>I have mysql column called categories. It can contain single or multiple values like this: 1 or 2 or 1,2,3 or 2,12...</p>
  
  <p>I try to get all rows containing value 2.</p>
  
  <pre><code>$query = "SELECT * FROM my_table WHERE categories LIKE '2'";
  $rows = mysql_query($query);
  </code></pre>
  
  <p>This returns row if column only has value 2 but not 1,2,3 or 2,12. How I can get all rows including value 2?</p>