shenliang_111 发表于 2011-7-9 22:07
看三段程序
1.%let repmonth=4;
%let repyear=2007;
%let repmword=%sysfunc(mdy(&repmonth,1,&repyear),monname9.);
2.
%let repmonth=4;
%let repyear=2007;
%let repmword=%sysfunc(%putn(mdy(&repmonth,1,&repyear)),monname9.));
3.
1.%let repmonth=4;
%let repyear=2007;
%let repmword=%sysfunc(%put(mdy(&repmonth,1,&repyear)),monname9.));

运行结果表明 1=2   3 error
请问各位好朋友，这是为什么？  两个层次：1  不用putn函数怎么也可以  2.putn可以 而 put却不可以呢？谢谢了