https://blog.csdn.net/yenange/article/details/50011721
http://www.cnblogs.com/jinzhenshui/archive/2012/04/18/2455210.html
http://www.cnblogs.com/kkun/archive/2009/07/01/1514640.html
https://docs.microsoft.com/en-us/previous-versions/sql/sql-server-2008-r2/ms162169(v%3dsql.105)
https://blog.csdn.net/iteye_18688/article/details/81525848
