title: Date subtraction in FlexibleSerchQuery
body: <p>I am trying to write a FlexibleSearchQuery to find records that are older than 30 days in hybris connected to a hsqldb database but the below code throws a </p>
  
  <pre><code>org.hsqldb.HsqlException: incompatible data types in combination
  </code></pre>
  
  <p>Query:</p>
  
  <pre><code>final FlexibleSearchQuery flexibleSearchQuery = new FlexibleSearchQuery("
  SELECT * FROM CUSTOMER AS c WHERE c.timestamp &lt; TRUNC(SYSDATE) - 30")
  </code></pre>
  
  <p>Could someone please advice on how to fix this issue ?</p>