title: MySQL WHERE IN condition with IFNULL function
body: <p>I have problem with IFNULL function used within WHERE IN condition:</p>
  
  <pre><code>SELECT provider_id FROM provider WHERE provider_id IN ( IFNULL("131, 132",'999') )
  </code></pre>
  
  <p>I tried all quoting alternatives like:</p>
  
  <pre><code> SELECT provider_id FROM provider WHERE provider_id IN ( IFNULL("'131', '132'", '999') )
  </code></pre>
  
  <p>But can not get this done with PHP.</p>
  
  <p>Could you please suggest how to correctly format the multi-value parameter within the IFNULL function?</p>