title: Regex substring with '|' in pattern
body: <p>I have a string of name|value pairs:</p>
  
  <pre><code>'clientName|img_0196.jpg||mime|||size|3195562||serverFileName|uplo/ad/548a5b35003bf.img_0196.jpg'
  </code></pre>
  
  <p>I'm trying to extract the value of the clientName, i.e. img_0196.jpg, with:</p>
  
  <pre><code>clientName := substring(eml from '%clientName.#"[^|]+#"%' for '#');
  </code></pre>
  
  <p>I've tried lots of patterns (different escaping of '|'), but they all yield either NULL or 'clientName'.<br>
  Help greatly appreciated.</p>