title: Multiple values in MySQL variable
body: <p>The following works as expected when there is a single value stored in a variable. </p>
  
  <pre><code>SET @a := "20100630";
  SELECT * FROM wordbase WHERE verified = @a;
  </code></pre>
  
  <p>But it does not work when there are multiple values stored in a variable.</p>
  
  <pre><code>SET @a := "'20100630', '20100701' ";
  SELECT * FROM wordbase WHERE verified in (@a);
  </code></pre>
  
  <p>Do I need to use prepared statements for this?</p>