title: Hybris Flexible search union query to fetch products
body: <pre><code>   code    Attribute1(String)
  
      A         C
      B         D
      C         Empty
      D         Empty 
  </code></pre>
  
  <p>how to get the pk's of all A,B,C,D</p>
  
  <p>Note: Using the string value C,D I want to fetch pk of product C,D along with A,B using Flexible search query</p>
  
  <p>Details :</p>
  
  <p>I Have list a of product's.</p>
  
  <p>Inside each of these products there is an attribute called "X" which contains product ID code of type string.</p>
  
  <p>Note : "Product ID Code" means "Product ID" of another product inside the list of products.</p>
  
  <p>Now i want to get pk's of products based upon the Product ID Codes?</p>