hibernate

-- select  后面没有加别名

Encountered a duplicated sql alias [id] during auto-discovery of a native-sql query

-- 看看数据库是否没有这个column

could not extract ResultSet

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session.createQuery(queryStr).list();　　//hql
session.createSQLQuery(queryStr).list();　　//普通sql

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hibernate 左连接：

@Test
    public void testLetfJion() {
        Session session = sessionFactory.getCurrentSession();
        session.beginTransaction();
        String queryStr = "select stu from com.bjsxt.hibernate.Student as stu left join com.bjsxt.hibernate.Teacher as te on stu.id = te.id";
        session.createQuery(queryStr).list();
        session.getTransaction().commit();
    }

报错：java.lang.IllegalStateException: DOT node with no left-hand-side!

正确写法：

    @Test
    public void testLetfJion() {
        Session session = sessionFactory.getCurrentSession();
        session.beginTransaction();
        String queryStr = "select stu from com.bjsxt.hibernate.Student as stu ,com.bjsxt.hibernate.Teacher as te where stu.id = te.id";
        session.createQuery(queryStr).list();
        session.getTransaction().commit();
    }

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IN适合于外表大而内表小的情况；EXISTS适合于外表小而内表大的情况。