本实例是在做小项目的时候用到的，想分享给大家，虽然简单，但可能对大家有用。！！！
实例：记账系统
一：
数据库： 流水记录，记录的消费类型有很多。如下图：通过typeId字段可以知道类型。(当然这里还有一张消费类型表哦)
二：sql语句查询
说明：主要是case语句的运用，根据不同情况，对不同的值进行sum运算得到我们想要的结果！
1 public List getSQLqueryColumnList(String sql) 2 { 3 List l=getSession().createSQLQuery(sql).list(); 4 return l; 5 6 }
baseDao是我各种基础数据库操作的函数，大家可以自行构建，其实主要是用上面的函数.
如果用的是hibernate 可以拿到sessionFactory sessionFactory.
SessionFactory.getCurrentSession() 得到session，再操作，即上述函数。
1 //查出各种钱钱钱钱钱钱钱的汇总！ 2 String Moneysql="select sum(case when typeid=1 then money else 0 end ) as cateen,"+ 3 "sum(case when typeid=2 then money else 0 end ) as car,"+ 4 "sum(case when typeid=3 then money else 0 end ) as entertainment,"+ 5 "sum(case when typeid=4 then money else 0 end ) as office,"+ 6 "sum(case when typeid=5 then money else 0 end ) as accommodation,"+ 7 "sum(case when typeid=6 then money else 0 end ) as traffic,"+ 8 "sum(case when typeid=7 then money else 0 end ) as service,"+ 9 "sum(case when typeid=8 then money else 0 end ) as gift,"+ 10 "sum(case when typeid=9 then money else 0 end ) as training,"+ 11 "sum(case when typeid=10 then money else 0 end ) as othermoney,"+ 12 "sum(money) as totalmoney "+ 13 "from db_workinfo.tb_daily_account where rigisteruser=‘wuhuanbin‘ and id between 2 and 30"; 14 15 List listForMoney=baseDao.getSQLqueryColumnList(Moneysql); 16 17 Iterator moneyIterator=listForMoney.iterator(); 18 Object[] o=(Object[])moneyIterator.next(); 19 System.out.println("餐饮"+o[0]); 20 System.out.println("车辆使用 "+o[1]); 21 System.out.println("项目娱乐 "+o[2]); 22 System.out.println("办公设备 "+o[3]); 23 System.out.println("住宿fe费 "+o[4]); 24 System.out.println("交通费 "+o[5]); 25 System.out.println("服务费 "+o[6]); 26 System.out.println("礼品费 "+o[7]); 27 System.out.println("培训费 "+o[8]); 28 System.out.println("其他费 "+o[9]); 29 30 System.out.println("总de费用: "+o[10]);
//查的是流水表，根据是消费类型ID哦！