Pageable sorting with specifications returns duplicated results - spring

Question

I have a Service entity that has a field Jobs which has Job entity in a ManyToMany relationship.
Filtering, sorting and pagination works perfectly, but the only problem is sorting by Jobs.
When I send a request to /serviceslist?sort=jobs&sortDir=asc I get duplicate results for each Service that has multiple jobs connected to it. To be more specific, if a Service has 4 jobs, the service gets returned 4 times and so on.
I think I should use groupBy, but how would I implement groupBy in my service below?
Service:
public Page<com.bitweb.syda.data.entity.service.Service> getServicesList(ServiceListRequest request, Pageable pageable) {
Specification<com.bitweb.syda.data.entity.service.Service> spec = where(null);
if (request.getSearch() != null) spec = spec.and(search(request.getSearch()));
if (request.getName() != null) spec = spec.and(name(request.getName()));
if (request.getJobs() != null) spec = spec.and(hasJobs(request.getJobs()));
if (request.getNeedsPatrol() != null) spec = spec.and(needsPatrol(request.getNeedsPatrol()));
return serviceRepository.findAll(spec, pageable);
}
Controller:
#RequestMapping(path = "/serviceslist", method = RequestMethod.GET)
public Page<ServiceResponse> getServicesList(
#RequestParam(defaultValue = "0") Integer page,
#RequestParam(defaultValue = "10") Integer size,
#RequestParam(required = false) String search,
#RequestParam(required = false) String name,
#RequestParam(required = false) String jobs,
#RequestParam(required = false) Boolean needsPatrol,
#RequestParam(defaultValue = "createTime") String sort,
#RequestParam(defaultValue = "asc") String sortDir
) {
ServiceListRequest request = new ServiceListRequest(search, name, jobs, needsPatrol);
Sort.Direction direction;
if (sortDir.equals("asc")) {
direction = Sort.Direction.ASC;
} else {
direction = Sort.Direction.DESC;
}
return serviceService.getServicesList(request, of(page, size, direction, sort))
.map(ServiceResponse::new);
}
Here are some examples what I've tried already:
public Page<com.bitweb.syda.data.entity.service.Service> getServicesList(ServiceListRequest request, Pageable pageable) {
Specification<com.bitweb.syda.data.entity.service.Service> spec = (root, query, builder) -> {
//you can do any check here if you want with the join and check all the search parameters here if you want
//Join<Object, Object> jobs = root.join("jobs");
// also set query to get distinct values
query.distinct(true);
return null;
};
if (request.getSearch() != null) spec = spec.and(search(request.getSearch()));
if (request.getName() != null) spec = spec.and(name(request.getName()));
if (request.getJobs() != null) spec = spec.and(hasJobs(request.getJobs()));
if (request.getNeedsPatrol() != null) spec = spec.and(needsPatrol(request.getNeedsPatrol()));
return serviceRepository.findAll(spec, pageable);
}
After trying this everything works as expected, but sorting by jobs gives me this error:
PSQLException: ERROR: for SELECT DISTINCT, ORDER BY expressions must appear in select list
Position: 652
I'm not very proficient with SQL and Criteria API and I don't know what I could do to fix this.
When using query.groupBy(root); instead of distinct, I get this error:
PSQLException: ERROR: column "job4_.id" must appear in the GROUP BY clause or be used in an aggregate function
Position: 780