Question

我正在尝试将以下SQL查询转换为HQL，并且遇到了一些问题。直线逐行转换不起作用，我想知道我是否应该在HQL中使用内连接？

        SELECT (UNIX_TIMESTAMP(cosc1.change_date) - UNIX_TIMESTAMP(cosc2.change_date)) 
        FROM customer_order_state_change cosc1  
        LEFT JOIN customer_order_state cos1_new on cosc1.new_state_id = cos1_new.customer_order_state_id  
        LEFT JOIN customer_order_state cos1_old on cosc1.old_state_id = cos1_old.customer_order_state_id  
        LEFT JOIN customer_order_state_change cosc2 on cosc2.customer_order_id = cosc1.customer_order_id  
        LEFT JOIN customer_order_state cos2_new on cosc2.new_state_id = cos2_new.customer_order_state_id  
        LEFT JOIN customer_order_state cos2_old on cosc2.old_state_id = cos2_old.customer_order_state_id 
        WHERE cos1_new.name = "state1" AND  cos2_new.name = "state2" and cosc2.change_date < "2008-11-06 09:00" 
AND cosc2.change_date > "2008-11-06 06:00" GROUP BY cosc1.change_date, cosc2.change_date ;

查询返回客户订单状态更改之间的时间（以秒为单位）。

状态名称和日期会动态插入到查询中。

编辑：刚试过这个

"SELECT (UNIX_TIMESTAMP(cosc1.changeDate) - UNIX_TIMESTAMP(cosc2.changeDate))" + 
        " FROM" + 
        " " + CustomerOrderStateChange.class.getName() + " as cosc1" +
        " INNER JOIN " + CustomerOrderStateChange.class.getName() +  " as cosc2" +
        " WHERE cosc1.newState.name = ?" +
        " AND cosc1.order.id = cosc2.order.id" + 
        " AND cosc2.newState.name = ?" +
        " AND cosc2.changeDate < ?" +
        " AND cosc2.changeDate > ?" + 
        " GROUP BY cosc1.changeDate, cosc2.changeDate";

并收到异常“外部或完整联接必须后跟路径表达式”

Answer 1

通常，您使用对象上的属性指定HQL连接，例如，如果类Foo和Bar和Foo.bar的类型为Bar，则from Foo f inner join f.bar as b是连接。据我所知，没有办法在HQL中执行自联接（我可能在这里错了）。

也就是说，Hibernate允许您使用session.createSQLQuery(...)编写（略微增强的）SQL查询。

Answer 2

结束更改以使用本机SQL和PreparedStatement，因为Hibernate的session.createSQLQuery（）似乎只适用于托管实体。

将SQL转换为HQL

2 个答案: