title: Need a MYSQL query to compare two tables and only output non matching results
body: <p>I have two tables in my database, one contains a list of items with other information on these items. The other table is contains a list of photographs of these items. </p>
  
  <p>The items table gives each item a unique identifier,which is used in the photographs table to identifier which item has been photographed.</p>
  
  <p>I need to output a list of items that are not linked to a photograph in the second table. Any ideas on how I can do this?</p>