a
add
add
test
Merge pull request #33 from zangpeng2p/master

藏鹏提交个人负责翻译包的信息
the first commit.a full section of 12.10:w
Merge remote-tracking branch 'mysql2cn/master'
21.md
Merge pull request #35 from guimingyue/master

第12章10节翻译内容
docs/Chapter_12/12.10.0_Cast_Functions_and_Operators.md
Merge pull request #38 from wufeirong/master

合并吴飞荣的分支
add info
WW
Merge pull request #40 from xiaotianhu/master

添加翻译信息
Merge pull request #39 from guimingyue/master

桂明月--12章10小节提交
Merge pull request #42 from wufeirong/master

吴飞荣-- 21章
Merge remote-tracking branch 'mysql2cn/master'