p******d
发帖数: 1120 | 1 Item 45 of 63 Mark item for review
To create a list of unique Customer_Id
values from the customer data set, which
of the following techniques can be used?
technique 1: proc SORT with NODUPKEY and OUT=
technique 2: data step with IF FIRST.Customer_Id=1
technique 3: proc SQL with the SELECT DISTINCT statement
A.
only technique 1
B.
techniques 1 and 2
C.
techniques 1 and 3
D.
techniques 1, 2, or 3
答案是D。我怎么觉得是C。题里没说这个数据是Sorted，这样的话 First.XXX得到的不
一定是Unique的答案呀。 | s*****9
发帖数: 285 | 2 只要用FIRST，就默认是SORTED了，FIRST得到的结果是UNIQUE的， |
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