title: wild expressions in mysql IN statement
body: <p>I want to use a WILDCARD for everything in the statement beneath:</p>
  
  <pre><code>"SELECT threads.*
      FROM thread_tag_map, threads, tags
      WHERE thread_tag_map.thread_id = threads.id
      AND thread_tag_map.tag_id = tags.id
  
      AND (tags.name IN ('WILDCARD'))";
  </code></pre>
  
  <p>What should I replace the WILDCARD with to be able to select every entry? I have tried ('*') but that doesn't work.</p>
  
  <p>I could drop the last row but the thing is that i am making this to a function. passing a value lets say <code>$value</code>, and the <code>$value</code> will replace WILDCARD. So when I pass 'computer' as <code>$value</code> it will get all rows for computer, but then I want to be able to pass nothing and the default <code>$value</code> will be a wildcard to select everything. So how can I make this possible?</p>