hibernate查询语句实例代码

一、聚集函数的使用：

• avg(...), sum(...), min(...), max(...)

• count(*)

• count(...), count(distinct ...), count(all...)

public DailyStatistics getPreviousDayStatistics(Integer dateNumber) {
        String hql = "from DailyStatistics bean where bean.dateNumber=" +
                    "(select max(ds.dateNumber) from DailyStatistics ds where ds.dateNumber<?  and ds.volumeZero=0)";
        Query query = getSession().createQuery(hql);
        query.setParameter(0, dateNumber);
        query.setMaxResults(1);
        System.out.println(query.getQueryString());
        return (DailyStatistics) query.uniqueResult();
}

二、单属性查询：

List list = session.createQuery("select name from Student").list();
for(Iterator iterator = list.iterator();iterator.hasNext();) {
    String name = (String)iterator.next();
    System.out.println(name);
}

三、多属性查询：

List list = session.createQuery("select id,name from Student").list();
for(Iterator iterator = list.iterator();iterator.hasNext();) {
    Object[] object= (Object[])iterator.next();
    //object[0]是id值,object[1]是name值
    System.out.println(object[0]+ "   "+object[1]);
}

四、返回实体类：

List list = session.createQuery("select new Student(id,name) from Student").list();
for(Iterator iterator = list.iterator();iterator.hasNext();) {
    Student student= (Student)iterator.next();
    System.out.println(student.getId()+ "   "+student.getName());
}

五、多个属性查询：

List list = session.createQuery("select s.id,s.name from Student as s").list();
for(Iterator iterator = list.iterator();iterator.hasNext();) {
    Object[] object= (Object[])iterator.next();
    System.out.println(object[0]+ "   "+object[1]);
}

或

List list = session.createQuery("select id,name from Student s").list();
for(Iterator iterator = list.iterator();iterator.hasNext();) {
    Object[] object= (Object[])iterator.next();
    System.out.println(object[0]+ "   "+object[1]);
}