Hibernate count映射问题

我就是我 2021-11-10 15:28 202阅读 0赞

问：hibernate， select name, count(\*) from table group by name。这句话应该怎么用HQL语句执行？或者在hibernate中该怎么查出每个name对应的count？

答：String hql = "select name, count(\*) from table group by name"; //跟sql语句差不多的，不过这里的name是类的属性，table 是类名，因为HQL是面向对象的查询的语言。

首先要获得session，你懂的，  
然后 Query query = session.createQuery(hql);  
List list = query.list();  
获取list里面的name ：  
Iterator it = lits.iterator();  
if(it.hasNext())\{  
Object\[\] obj = (Object\[\]) it.next();  
String name = obj\[0\];  
int count = obj\[1\];  
\}

在项目开发中的具体情况：

//关键是处理count映射问题。120221 hjl  
                    String q = "select userId, nickName, count(id)  from BbscsLogintimes  where LoginYear = ? and LoginMonth = ?  group by userId order by col_2_0_ desc";  
         
                    Query query = session.createQuery(q);  
                    query.setLong(0, Long.valueOf(year));  
                    query.setLong(1, Long.valueOf(mon));    
                    List list = query.list();      
                      
                    //封装  
                    List list2 = new ArrayList();  
                    BbscsLogintimes logintimes= null;  
                    Iterator it = list.iterator();  
                    long j = 1;  
                    while(it.hasNext()){  
                        logintimes = new BbscsLogintimes();  
                        Object[]  obj = (Object[]) it.next();  
                        logintimes.setOrderId(j);  
                        logintimes.setOrderName((String) obj[1]);  
                        logintimes.setOrderNum((Integer)obj[2]);  
                        list2.add(logintimes);  
                        j++;  
                    }

以上转载自： [http://simpledev.iteye.com/blog/1433282][http_simpledev.iteye.com_blog_1433282]

此为本人项目中的具体代码：（\*\*\*DaoImpl.java）

需求：查询出 ××人（字段：userId）购买了 ×× （字段：number）注幸运码

@Override
        public List<UserLottery> listUserLotteryQuantity(int drawNum) {
           Query query =  entityManager.createNativeQuery("SELECT ul.user_id, count(ul.user_id) AS numQuantity FROM user_lottery_history ul WHERE ul.draw_num =:drawNum GROUP BY ul.user_id ORDER BY ul.user_lottery_history_id DESC LIMIT 10")
                   .setParameter("drawNum", drawNum);
           List list = query.getResultList();
           List<UserLottery> ulList = new ArrayList<UserLottery>();
           UserLottery ul = null;
           User user = null;
           Iterator it = list.iterator(); 
           while(it.hasNext()) {
               Object[]  obj = (Object[]) it.next();  
               ul = new UserLottery();
               user = new User();
               user.setUserId(((BigInteger) obj[0]).longValue());
               ul.setUser(user);
               ul.setNumber(obj[1].toString());
               ulList.add(ul);
           }
           return ulList;
        }

[http_simpledev.iteye.com_blog_1433282]: http://simpledev.iteye.com/blog/1433282