mysql 累加排序求名次

自己做的一个小项目里需要用mysql计算一些信息。

mysql中的 表如下（注：表中数据都是测试数据，随机生成的）

mysql> select * from shake_log;
+-----+-------------+--------+---------------------+------+
| id  | mobile      | credit | time                | type |
+-----+-------------+--------+---------------------+------+
|    |  |    1.3 | -- :: |     |
|    |  |    0.3 | -- :: |     |
|    |  |    0.3 | -- :: |     |
|    |  |    0.2 | -- :: |     |
|    |  |    0.5 | -- :: |     |
。。。。。。
。。。。。。
|  |  |    0.5 | -- :: |     |
|  |  |    0.2 | -- :: |     |
|  |  |    0.2 | -- :: |     |
|  |  |    0.3 | -- :: |     |
。。。。。。
。。。。。。

这张表的含义是这样的，每一条记录代表一次获益，而每个mobile的获益就是当天所有的记录的累加和。

例如上面的记录18369905226有三条记录，那么他今天的获益就是 0.5+0.2+0.2+0.3 = 1.2

1. 求获益最多的mobile和值

select mobile, sum(credit) as sumCredit from shake_log where time between '2014-12-06 00:00:00' and '2014-12-06 23:59:59' group by mobile order by sumCredit desc limit 1;

修改成hql语句，在java中如下:

public CreditRank queryRank(int year, int month, int day) {

        String hql = "select mobile, sum(credit) as sumCredit, time from CreditLog"
                + " where year(time) = ? and month(time) = ? and day(time) = ?"
                + " group by mobile order by sumCredit desc";

        Query query = currentSession().createQuery(hql);

        query.setFirstResult(0);
        query.setMaxResults(1);

        query.setParameter(0, year);
        query.setParameter(1, month);
        query.setParameter(2, day);

        List<Object[]> objsList = query.list();
        Object[] firstObjs = objsList.get(0);

        return new CreditRank(1, (String)firstObjs[0], (Double)firstObjs[1]);
    }

2. 求某一具体的mobile按总获益算得的名次

select rank from (select @counter:=@counter+1 as rank, mobile, sumCredit from (select mobile, sum(credit) as sumCredit from shake_log where time between '2014-12-06 00:00:00' and '2014-12-06 23:59:59' group by mobile order by sumCredit desc) as sumList, (select @counter:=0) as t) as rankList where mobile='';

这一部分没有转成hql， 因为hibernate不支持from子查询。

那就使用hibernate直接调用sql语句。

public CreditRank queryRank(String mobile, int year, int month, int day) {

        String sql = "select rank, mobile, sumCredit " +
                "from (select @counter\\:=@counter+1 as rank, mobile, sumCredit " +
                "from (select mobile, sum(credit) as sumCredit from shake_log " +
                " where year(time) = :year and month(time) = :month and day(time) = :day " +
                "group by mobile order by sumCredit desc) as sumList, (select @counter\\:=0) as t) as rankList " +
                "where mobile = :mobile";

        SQLQuery query = currentSession().createSQLQuery(sql)
                .addScalar("rank", StandardBasicTypes.INTEGER)
                .addScalar("mobile", StandardBasicTypes.STRING)
                .addScalar("sumCredit", StandardBasicTypes.DOUBLE);

        // 设置参数
        query.setParameter("year", year);
        query.setParameter("month", month);
        query.setParameter("day", day);
        query.setParameter("mobile", mobile);

        // 查询
        List<Object[]> objsList = query.list();

        if (objsList.size() == 0) {
            return null;
        }

        Object[] firstObjs = objsList.get(0);

        // 封装
        CreditRank creditRank = new CreditRank((Integer)firstObjs[0], (String)firstObjs[1], (Double)firstObjs[2]);

        return creditRank;
    }

需要注意:

:= 要 \\:= 才能被识别