QueryDsl with GroupBy and Paging

[Bob Wilson]

Is there a way to implement a groupBy queryDsl statement that includes paging? It appears that using groupBy and transform you end up with a map and I have not seen any documentation around implementing paging with grouping. 

Map<String, PcServiceConnection> results = getQuerydsl().createQuery(qPcServiceConnection).

                where(qPcServiceConnection.targetOrgId.in(targetOrgIds)).

                transform(groupBy(qPcServiceConnection.patientEpisodeDocKey).as(Projections.bean(PcServiceConnection.class, qPcServiceConnection.patientEpisodeDocKey,

                        qPcServiceConnection.patientReferralDocKey, qPcServiceConnection.pcServiceConnectionId)));

        */

[timowest]

The paging (limit/offset) applies to the query and not result aggregation. Paging at the result aggregation is not supported.

Could you explain your requirement for that?

[Bob Wilson]

I have a query like this that does a groupBy for aggregation and creates a list of objects. I have not been able to find the syntax - or if it is possible - to integrate paging and sorting into a query that does grouping:.

      

       Collection customers = getQuerydsl().createQuery(qCustomer).

       where(qCustomer.customerId.in(targetIds)).

       transform(groupBy(qCustomer.ssn).

           as(Projections.bean(Customer.class, qCustomer.Id,

                 qCustomer.ssn, qCustomer.name))).

       values(); 

[Alan C.]

Hello Bob,

Hope this fits you well, but for us with latest version, we tried this approach. The only problem we have, is that we want to sort by a counter on a property. It's not working, but for other values it does.

final var querydsl = new Querydsl(entityManager, (new PathBuilderFactory())

.create(ConfigElement.class));

JPAQueryFactory queryFactory = new JPAQueryFactory(entityManager);
JPAQuery<ConfigElement> configElementJPAQuery = queryFactory
.selectDistinct(configElement).from(configElement)
.leftJoin(configElement.milestones, milestone)
.leftJoin(configElement.reviews, review)
.where(configElementsFilter)
.orderBy(orderSpecifiers);

final List<?> result = querydsl.applyPagination(pageable, configElementJPAQuery).fetchAll().fetch();

Greets,