Java 按分组的Hibernate查询

如何将此postgreSql查询转换为hibernate查询：

select sum(amount), cat_id, 
       date_trunc('month', createOn) as month,
       date_trunc('year', createOn) as year 
from item 
where owner_id = 1 
group by cat_id , month, year;

我的项目类别为：

@Column(name="AMOUNT")
private BigDecimal amount;

@ManyToOne
@JoinColumn(name="OWNER_ID")
private Customer owner;


@ManyToOne(fetch=FetchType.EAGER)
@JoinColumn(name="CAT_ID")
private Category category;

@Temporal(TemporalType.DATE)
@Column(name="CREATEON")
private Date createOn;

我已尝试将其转换为：

StringBuffer hql = new StringBuffer()
        .append("Select sum(amount), category, month(createOn) as mon, year(createOn) as year")
        .append(" from Item")
        .append(" where owner=:owner")
        .append(" group by category, mon, year");

    Query query = getQuery(hql.toString())
                    .setParameter("owner", owner);   

    List<Object[]> resultList = query.list();
    List<BundleHolder> bundleHolderList = new ArrayList<BundleHolder>();

    for(Object[] result : resultList) {
        BundleHolder instance = BundleHolder.getInstance();
        instance.setAmount((BigDecimal) result[0]);
        instance.setCategory((Category) result[1]);
        instance.setMonth((int) result[2]);
        instance.setYear((int) result[3]);

        bundleHolderList.add(instance);
    }

---

我尝试将category切换到cat\u id，或将owner切换到owner\u id（将参数设置为owner.getId（）），但也没有帮助。

您需要将

category

更改为

category.id

：

StringBuffer hql = new StringBuffer()
        .append("Select sum(amount), category.id, month(createOn) as mon, year(createOn) as year")
        .append(" from Item")
        .append(" where owner=:owner")
        .append(" group by category.id, mon, year");

---

使用类似于

的别名，从项目中选择sum（item.amount）、item.category、month（item.createOn）作为mon、year（item.createOn）作为year，其中item.owner=：owner group by item.category、mon、year

。（稍后，删除

FetchType.EAGER

，并使用其他方案，如fetch join）。谢谢，我尝试了您的查询，但它抱怨我需要在group by中包含item.category.id。因此，我通过在“选择和分组依据”中更改item.category->item.category.id来修复它。结果令人着迷。谢谢你的建议。

StringBuffer hql = new StringBuffer()
        .append("Select sum(amount), category.id, month(createOn) as mon, year(createOn) as year")
        .append(" from Item")
        .append(" where owner=:owner")
        .append(" group by category.id, mon, year");