title: MySQL efficient SELECT query
body: <p>I'm not a database professional, but currently working on one query (PHP->MySQL):</p>
  
  <p>I have 3 tables:</p>
  
  <p>'Items': id, name, link</p>
  
  <p>'ItemsToUsers': id, item_id, user_id</p>
  
  <p>'Users': id, email</p>
  
  <p>Each 'Item' availability is submitted to regular changes which I check on fly by some algorithm.</p>
  
  <p>My goal is to</p>
  
  <p>1) SELECT all Items and check on fly if they are available</p>
  
  <p>2) If Item is available, notify users who are monitoring it by email. For that I need to SELECT users from 'ItemsToUsers' and then get their emails from Users table.</p>
  
  <p>I know how to do it in a straightforward way, but I feel that I will fall into running to many queries. (individual SELECT for every user...)</p>
  
  <p>Is there a way to do it more efficiently: in one query or by changing the algorithm?
  Thank you for your time!</p>