小编use*_*050的帖子

我是hibernate的新手,我遇到了以下问题:我得到了"期望加入的路径!" 我尝试运行此查询时出现异常:

String hql = "select avg(t.price) from Ticket t JOIN Flight f WHERE f.number = '" + flightNumber + "'";
Query query = this.session.createQuery(hql);        
List<Double> list = query.list();

我想选择已经为特定航班出售的机票的平均价格.

我已经检查了这些链接,但是我没有解决我的问题: HQL左连接:加入 hql内连接的路径期望加入的路径!错误

我的代码是:

Flight.hbm.xml

<?xml version="1.0"?><!DOCTYPE hibernate-mapping PUBLIC
 "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
 "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
    <class name="pck.Flight" table="flight" catalog="airbook">
        <id name="id" type="java.lang.Integer">
            <column name="id" />
            <generator class="identity" />
        </id>
        <many-to-one name="sourceairport" class="pck.Sourceairport" fetch="select">
            <column name="sourceairportid" />
        </many-to-one>
        <many-to-one name="destinationairport" class="pck.Destinationairport" fetch="select">
            <column name="destinationairportid" />
        </many-to-one>
        <property name="number" type="string">
            <column …