1、你用的命令是老版本sata的命令，新版是不同的格式

2、帮助里面的介绍

    sorted specifies that the master and using datasets are already sorted by varlist.  If the datasets are already
        sorted, then merge runs a little more quickly; the difference is hardly detectable, so this option is of
        interest only where speed is of the utmost importance.
3、你自己也可以试试啊
     学软件就是要自己尝试

尝试很重要！