title: Mysql Error executing simple code
body: <p>I made a SQL request with a function that already works and look like this :</p>
  
  <pre><code>SELECT fnStripTags('this &lt;html&gt;is &lt;b&gt;a test&lt;/b&gt;, nothing more&lt;/html&gt;');
  </code></pre>
  
  <p>When I execute this SQL code:</p>
  
  <pre><code>INSERT INTO `ps_product_lang` (`description`) VALUES (
      SELECT fnStripTags(description) FROM ps_product_lang 
      WHERE ps_product_lang.id_lang = id_lang AND ps_product_lang.id_product = id_product 
  ) WHERE description IS NOT NULL
  </code></pre>
  
  <p>I got this error:</p>
  
  <pre><code>1064 - You have an error in your SQL syntax; check the manual that
  corresponds to your MySQL server version for the right syntax to use
  near 'SELECT fnStripTags(ps_product_lang.description) FROM
  ps_product_lang WHERE ps_pr' at line 1
  </code></pre>