小编tom*_*gal的帖子

在开发Ruby on Rails应用程序的过程中,我不断追踪开发日志tail -f log/development.log.

我几周前才开始在Rails中开发,所以我不知道日志是否总是显示这么多条目,但我相信资产最近刚刚添加到3.1中.无论如何,这是我development.log的页面调用的一个例外:

Started GET "/assets/reset.css?body=1" for 70.63.17.68 at Wed Oct 12 20:10:49 +0000 2011
Served asset /reset.css - 304 Not Modified (1ms)


Started GET "/assets/style.css?body=1" for 70.63.17.68 at Wed Oct 12 20:10:49 +0000 2011
Served asset /style.css - 304 Not Modified (0ms)


Started GET "/assets/application.css?body=1" for 70.63.17.68 at Wed Oct 12 20:10:49 +0000 2011
Started asset /application.css - 304 Not Modified (0ms)


Started GET "/assets/application.js?body=1" for 70.63.17.68 at Wed Oct 12 20:10:49 …

Table 1              Table 2
Number | Code        Code | Description
1234     A           A      Something
1235     B           C      Something else
1246     C           D      Something other
1247     A
1248     B
1249     A

我想找到不同的Code值并得到这样的回报:

1  |  2
-------
A     A
B
C     C
      D

我无法弄清楚如何编写一个可以返回上述结果的SQL查询.任何人都有这样或类似的查询经验？