诸位大侠请看题
the SAS data set work.temp is indexed on the variable id:
id amount
p 52
p 45
a 13
a 56
r 34
r 12
r 78
the following SAS program is submitted:
proc print data=work.temp;
[_insert_BY_statement]
run;
which by statement completes the program creates a listing report that is grouped by id. and completes without errors?
A: by id; B: by id grouped; C: by id descending; D: by descending id;
首选答案应该从A 或者D里面选。但是因为该数据集为 index,所以,在SAS里面运行,二者都带有错误。
请大家帮小弟看看,为什么答案是 A? 非常感谢