如何使用分组进行条件查询

Question

select CreatedBy, count(*) as cnt
from fourwheelerquoteresponse
group by CreatedBy
order by count(*) desc
limit 5;

这是我的 sql 我根据 JPA 标准想要它 API 仍然不确定这是我的查询，它返回整个列表而不考虑组

@Override
public List<FourWheelerQuoteResponseEntity> findAllByTopOrLow(String createdBy) {
    CriteriaBuilder criteriaBuilder = entityManager.getCriteriaBuilder();
    CriteriaQuery<FourWheelerQuoteResponseEntity> criteriaQuery = criteriaBuilder.createQuery(FourWheelerQuoteResponseEntity.class);
    Root<FourWheelerQuoteResponseEntity> root = criteriaQuery.from(FourWheelerQuoteResponseEntity.class);
    Expression<String> groupByExp = root.get("createdBy").as(String.class);
    Expression<Long> countExp = criteriaBuilder.count(groupByExp);
    CriteriaQuery<FourWheelerQuoteResponseEntity> select =
    criteriaQuery.multiselect(groupByExp, countExp);
    criteriaQuery.groupBy(groupByExp);
    criteriaQuery.orderBy(criteriaBuilder.desc(countExp));

    criteriaQuery.select(root)
     .where(criteriaBuilder.equal(root.get("createdBy"), createdBy));

    try {
        return entityManager.createQuery(select).getResultList();   
    } catch (NoResultException nre) {
        return null;
    } catch (NonUniqueResultException nure) {
        return null;
    }
}

Answer 1

在 MySQL (?) 或 Hibernate 上表达查询的语法非常相似：

select entity.createdBy, count(entity)
from FourWheelerQuoteResponseEntity entity
group by entity.createdBy
order by count(entity) desc
limit 5

Answer 2

参考下面的代码，我相信这会解决你的问题。如果没有，请告诉我

@Override
    @Transactional(readOnly = true)
    public Map<String,Long> topOrLowFew(List<String> userIdList,String order,int howMany) {
        CriteriaBuilder criteriaBuilder = entityManager.getCriteriaBuilder();
        CriteriaQuery<Tuple> criteriaQuery = criteriaBuilder.createQuery(Tuple.class);
        Root<FourWheelerQuoteResponseEntity> root = criteriaQuery.from(FourWheelerQuoteResponseEntity.class);
        criteriaQuery.groupBy(root.get("createdBy"));
        if(order.equals("desc")) {
            criteriaQuery.orderBy(criteriaBuilder.desc(criteriaBuilder.count(root)));
        }
        if(order.equals("asc")) {
            criteriaQuery.orderBy(criteriaBuilder.asc(criteriaBuilder.count(root)));
        }
        criteriaQuery.multiselect(root.get("createdBy"), criteriaBuilder.count(root));
        criteriaQuery.where(criteriaBuilder.and(criteriaBuilder.in(root.get("createdBy")).value(userIdList)));
        List<Tuple> resultList = entityManager.createQuery(criteriaQuery).setMaxResults(howMany).getResultList();
        Map<String,Long> orderedMap = new LinkedHashMap<String,Long>();
        for ( Tuple tuple : resultList ) {
              String userId = (String) tuple.get( 0 );
              Long count = (Long) tuple.get( 1 );
              orderedMap.put(userId, count);
            }
        return orderedMap;
    }

如何使用分组进行条件查询

How to make Criteria Query with grouping

hibernate

jpa

criteria-api