Example table:
示例表：
id computer app version build date
---|---------|------|------------|-------|---------
1 | aaaa1 | app1 | 1.0.0 | 1 | 2013-11-11 09:51:07
2 | aaaa1 | app2 | 2.0.0 | 2 | 2013-11-12 09:51:07
5 | xxxx2 | app1 | 1.0.0 | 1 | 2013-11-13 09:51:07
3 | cccc3 | app2 | 3.1.0 | 1 | 2013-11-14 09:51:07
4 | xxxx2 | app1 | 1.0.0 | 2 | 2013-11-15 09:51:07
5 | cccc3 | app2 | 3.1.1 | 3 | 2013-11-16 09:51:07
6 | xxxx2 | app1 | 1.0.2 | 1 | 2013-11-17 09:51:07
7 | aaaa1 | app1 | 1.0.2 | 3 | 2013-11-18 09:51:07
id computer app 
