title: MySQL search for value or value = NULL?
body: <p>I can't figure out how to do a filter in MySQL for a value or NULL?</p>
  <p>Here's a simple contrived example.  We have a sports team. Multiple tables. Everybody is in the process or ordering a t-shirt. And for a contrived use case, the t-shirt manufacturer says red shirts are no longer available. We want to order a new t-shirt for everyone on the team who hasn't yet ordered or had an order for a red shirt.  And after a join, I see the following:</p>
  <p>Post join result showing name and color choice (less any filtering):</p>
  <pre><code>Adam       red
  Beth       blue
  Craig      NULL
  Dawn       NULL
  Edith      red
  Frank      blue
  Gabriel    NULL
  </code></pre>
  <p>As part of that join, I'd really like to have just the result showing folks with red or NULL choices. I'm doing the test sql joins and WHERE filtering in a phpmyadmin panel in the browser.  The &quot;NULL&quot; values show up as italic characters in lighter font color.</p>
  <p>I've tried every combination of <code>...WHERE 'color' = &quot;red&quot; or 'color' = NULL</code>, also <code>...WHERE 'color' = &quot;red&quot; or 'color' = &quot;&quot;</code> that I can come up with. Generally I get a empty set of values as a result.  Obviously, in the above example, I'd expect to see a list containing just <code>Adam, Craig, Dawn, Edith, and Gabriel</code> in my query results.</p>
  <p>Is there a trick here?  Note, my actual joins are a little bit involved and the data is confidential.</p>