Hibernate count如何映射？HQL別名字段問題？

問：hibernate， select name, count(*) from table group by name。這句話應該怎麼用HQL語句執行？或者在hibernate中該怎麼查出每個name對應的count？

 

答：String hql = "select name, count(*) from table group by name";   //跟sql語句差不多的，不過這裏的name是類的屬性，table 是類名，因爲HQL是面向對象的查詢的語言。

首先要獲得session，你懂的，
然後  Query query = session.createQuery(hql);
List list = query.list();
獲取list裏面的name ：
Iterator it = lits.iterator();
if(it.hasNext()){
    Object[]  obj = (Object[]) it.next();
    String name = obj[0];
    int count = obj[1];
}

 

在項目開發中的具體情況：

//關鍵是處理count映射問題。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();	 
	            
	            //封裝
	            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++;
	            }

 

說明：HQL別名字段

hibernate執行時打印出HQL
<property name="show_sql">true</property>

Hibernate: select bbscslogin0_.UserID as col_0_0_, bbscslogin0_.NickName as col_1_0_, count(bbscslogin0_.ID) as col_2_0_ from bbscs6.bbscs_logintimes bbscslogin0_ where LoginYear=? and LoginMonth=? group by bbscslogin0_.UserID order by col_2_0_ desc limit ?

UserID別名 ~ col_0_0_
NickName別名 ~ col_1_0_
count(bbscslogin0_.ID)別名 ~ col_2_0_

所以上面的HQL語句：group by userId order by col_2_0_ desc  //按count統計量來降序排列。

 

 

 

 

 

 

 

 

 

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