Hibernate HQL select 不同于 where order by query

Question

我正在更新一个项目以明确了解客户，之前假设客户是因为我们只有一个...

我的问题是在我的 HQL 查询中添加 where 子句。

我的起点是这个查询：

  public static final String SELECT_DISTINCT_STORES =
        "select DISTINCT e.storeNum, e.city, e.state from BoEngagement e order by e.storeNum";

我想添加一个 where e.customer_fk = :customer_fk 子句，但每次我添加 where 子句时都会出现各种 org.hibernate.hql.internal.ast.QuerySyntaxException 错误，除非我删除 distinct 关键字，但随后我我不相信查询会给我所期望的结果。

这个有效：

   "select e.storeNum, e.city, e.state from BoEngagement e WHERE e.customer_fk = :customer_fk";

而且，如果我要如此简化查询，那真的应该是

"select e from BoEngagement e WHERE e.customer_fk = :customer_fk";

但是，正如我所说，我不相信删除 distinct 关键字是我想要做的。

以下是我尝试过的一些方法：

   "select DISTINCT e.storeNum, e.city, e.state FROM BoEngagement e WHERE e.customer_fk = :customer_fk order by e.storeNum";

出现这个错误

[ERROR] 2019-10-18 15:10:03.449 [main] BsRetrieveDistinct - java.lang.IllegalArgumentException: org.hibernate.hql.internal.ast.QuerySyntaxException: unexpected token: FROM near line 1, column 94 [SELECT DISTINCT e.city, e.state from com.bh.radar.bo.BoEngagement e order by e.state, e.city FROM com.bh.radar.bo.BoEngagement e WHERE e.customer_fk = :customer_fk]
java.lang.IllegalArgumentException: org.hibernate.hql.internal.ast.QuerySyntaxException: unexpected token: FROM near line 1, column 94 [SELECT DISTINCT e.city, e.state from com.bh.radar.bo.BoEngagement e order by e.state, e.city FROM com.bh.radar.bo.BoEngagement e WHERE e.customer_fk = :customer_fk]

和这个更复杂的版本

   "select DISTINCT e.storeNum, e.city, e.state FROM BoEngagement e in " +
        "(select g FROM BoEngagement g WHERE g.customer_fk = :customer_fk order by g.storeNum)";

出现这个错误

[ERROR] 2019-10-18 15:08:14.317 [main] BsRetrieveDistinct - java.lang.IllegalArgumentException: org.hibernate.hql.internal.ast.QuerySyntaxException: unexpected token: in near line 1, column 81 [select DISTINCT e.storeNum, e.city, e.state FROM com.bh.radar.bo.BoEngagement e in (select g FROM com.bh.radar.bo.BoEngagement g WHERE g.customer_fk = :customer_fk order by g.storeNum)]
java.lang.IllegalArgumentException: org.hibernate.hql.internal.ast.QuerySyntaxException: unexpected token: in near line 1, column 81 [select DISTINCT e.storeNum, e.city, e.state FROM com.bh.radar.bo.BoEngagement e in (select g FROM com.bh.radar.bo.BoEngagement g WHERE g.customer_fk = :customer_fk order by g.storeNum)]

显然我不完全理解HQL，还有distinct关键字。我做错了什么？

编辑：

@JB Nizet 评论说，根据我发布的错误，他认为我运行不是我发布的查询。我绝对是运行那个查询。我的困惑是为什么我写的 HQL 在 SQL 中生成两个 FROM 子句。我在下面粘贴了一个屏幕截图，其中显示了相关代码和错误消息。

Answer 1

也许这不是我最初问题的答案，但在互联网上搜索了好几天并 post 在这里提出我的问题并没有发现任何可以从各种 JPQL 字符串生成合理的 PostgreSQL 查询的东西我试过了，所以我偶然发现了这个博客 post：The Many Faces of DISTINCT in PostgreSQL

然后开始研究 EntityManager.createNativeQuery 方法，并提出了这个有效的 PostgreSQL 查询：

  public static final String SELECT_DISTINCT_STORES =
         "SELECT DISTINCT ON(storeNum, city, state) * FROM radar2.engagement WHERE customer_fk = :customer_fk ORDER BY storeNum asc, city, state";

我这样使用它：

    results = em.createNativeQuery(SELECT_DISTINCT_CITY_STATES, BoEngagement.class)
                .setParameter("customer_fk", customer_fk)
                .getResultList();

现在，此解决方案特定于 PostgreSQL，但这是我现在和未来无限期使用的数据库。

Hibernate HQL select 不同于 where order by query

Hibernate HQL select distinct from where order by query

java

postgresql

hibernate

hql