求sql语句

Question

table_a:
id  ip              data               time
1   192.168.100.1     2               2011-07
2   192.168.100.1     2               2011-07
3   192.168.100.1     3               2011-07
4   192.168.100.1     3               2011-07
5   192.168.100.2     4               2011-07
6   192.168.100.2     4               2011-07
7   192.168.100.2     4               2011-07
8   192.168.100.2     4               2011-07想得到如下结果：
ip              sum_data               time
192.168.100.1       10                 2011-07
192.168.100.12      16                 2011-07sql语句如何实现？？

Answer 1

mysql> select ip,sum(data),time from a group by ip,time;
+---------------+-----------+---------+
| ip            | sum(data) | time    |
+---------------+-----------+---------+
| 192.168.100.1 |        10 | 2011-07 |
| 192.168.100.2 |        16 | 2011-07 |
+---------------+-----------+---------+
2 rows in set (0.01 sec)

Answer 2

select ip,time,sum(data) from tt group by ip,time;