title: Count in QueryDSL grouping transformer
body: <p>Is it possible to get the count of aggregating results when using groupby processing in QueryDSL? I have the following query:</p>
  
  <pre><code>query.from(catalog)
  .innerJoin(qe).on(catalog.id.eq(qe.itemId))
  .innerJoin(enterprise).on(enterprise.id.eq(qe.enterpriseId))
  
  .leftJoin(catalogPerson).on(catalogPerson.catalogId.eq(catalog.id))
  
  .where(catalog.deletionDate.isNull(), qe.enterpriseId.eq(org) )
  
  .orderBy(catalog.creationDate.desc())
  
  .limit(limit)
  .offset(offset)
  
  .transform(groupBy(catalog.id).as(Projections.constructor(Catalog.class,
                                  catalog.id,
                                  catalog.name,
                                  catalog.code,
                                  // //GET THE NUMBER OF CATALOG PERSONS'
                                  )));
  </code></pre>
  
  <p>and I want to get the count of persons belonging to the certain catalog.</p>
  
  <p>Thanks</p>