我想做一个简单的windows 8应用程序。我在电脑上安装了:
OS : Windows 8 pro
Visual studio 2013
SDK 8.0
当我调试我的应用程序时,它会出现以下错误:
Deployment failed because no Windows Phone was detected. Make sure a phone is connected and powered on.
为了解决此错误,当我安装Windows8.1仿真程序时,它会在下面给出错误:
This computer does not support the windows phone emulato
我需要编写一个查询来获取用户的二级连接。
假设有四个朋友:A,B,C,D
A is friend with B
B is friend with C and D
现在我想找到A,即C和D的二级连接
数据库设计
表:用户
id name
1 A
2 B
3 C
4 D
表: user_friends
id friend1 friend2
1 1 2
2 2 3
3 2 4
有人能帮我查询吗?