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The SAS data sets Work.Employee and Work.Salary are shown below.
Work.Employee
fna me age
Bruce 30
Dan 40
Work.Salary
fname salary
Bruce 25000
Bruce 35000
Dan 25000
The following merged SAS data set is generated:
Work.Empdata
fname age totsal
Bruce 30 60000
Dan 40 25000
Which one of the following SAS programs created the merged data set?


b. data work.empdata(drop=salary);
merge work.employee
work.salary;
by fname;

if first.fname then totsal=0;
totsal+salary;
if last.fname then output;
run;
c. data work.empdata;
merge work.employee
work.salary(drop=salary);
by fname;
if first.fname then total=0;
totsal+salary;
if last.fname then output;
run;
为什么B对？我认为C对啊？drop这里到底应该写在哪里呢？

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关键词：drop following generated Employee programs generated following programs created

如果选c的话，work.salary中的salary变量不读入，那就无法计算total变量，所以很明显C 不对。而merge后的data set ：Work.Empdata中不含salary这个变量，所以drop应该放在Work.Empdata后面。