[英]SAS create a flag in table1 if variable is present in table2
I have two tables about the course of each student in 2 classes, and I want to create a binary variable flag
in Table1 which presents the presence of variable course
in Table2 for each student. 我有两个关于每个学生在2个班级中的课程的表格,我想在Table1中创建一个二进制变量
flag
,该flag
表示每个学生在Table2中存在变量course
。
Table1: 表格1:
class student course
1 A 001
1 A 004
2 B 003
Table2: 表2:
class student course
1 A 002
1 A 004
2 B 003
Expected result: 预期结果:
Table1: 表格1:
class student course flag
1 A 001 0
1 A 004 1
2 B 003 1
I've tried the suivant program: 我已经尝试过辅助程序:
proc sql;
create table common as
select A.*, B.*
from Table1 A
inner join Table2 B
on A.class=B.class and A.student=B.student and A.course=B.course;
quit;
That only outputs the rows in common and I didn't succeed to create a flag. 那只会输出共同的行,而我没有成功创建一个标志。
Hope to get your answer. 希望得到你的答案。 Thanks!
谢谢!
Here is one method: 这是一种方法:
proc sql;
create table common as
select a.*,
(case when exists (select 1 from table2 b where A.class=B.class and A.student=B.student and A.course=B.course)
then 1 else 0
end) as flag
from table1 a;
Just use a MERGE and the IN= dataset options. 只需使用MERGE和IN =数据集选项。
data want ;
merge table1(in=in1) table2(in=in2);
by class student course;
if in1 ;
flag=in2;
run;
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