stata还不错呀

我觉得各有各的好处。不能一概而论。

stata没有这个功能。It's not necessary, every time, you can only work with one data, and stata holds working data in memory, so may need lot of memory with big data, SAS is better and efficient in handling very large data, especial with the use of sql.  But stata is cheaper and update quickly with more modern or newest methods.  Personally, I prefer to use Stata except when I have to use SAS.

软件各有所长
但如果说对数据的处理，stata在许多方面要比sas方便很多
如：reshape、egen等命令
只是stata的数据接口不如sas的强大而已。

至于各种模型估计等方面，你可以看ucla网站上的例子，对比，那个程序更加简洁和方便。
http://www.ats.ucla.edu/stat/dae/
http://www.ats.ucla.edu/stat/stata/webbooks/default.htm
http://www.ats.ucla.edu/stat/stata/examples/default.htm


最好把下面链接的那篇文章仔细看看，
10、ucla对stata、R、sas和spss三个软件的技术报告
Strategically using General Purpose Statistics Packages: A Look at Stata, SAS and SPSS
https://bbs.pinggu.org/thread-349743-1-1.html

thank u so much!