Is it possible to calculate the percentage of some category for each group, using proc sql?

[YiqunDai]

I have a dataset as follows. And I want to get the percentage of students with A, B, or C for each class, is it possible to do by Proc SQL? Thank you so much.

--------------------

ID   Credit  Class

--------------------

1     A         1

2     B         1

3     B         1

4     C         1

5     A         1

6     A         2

7     C         2

8     C         2

9     C         2

10   B         2

-------------------

And the result I want to get is

-----------------------

Class  A    B    C

-----------------------

1        0.4  0.4  0.2

2        0.2  0.2  0.6

----------------------

[collinelliot · Accepted solution]

You can calculate the average of a boolean reponse:

data have;
    input credit $ class;
datalines;
A         1
B         1
B         1
C         1
A         1
A         2
C         2
C         2
C         2
B         2
;

proc sql;
    SELECT class, 
           mean(credit = 'A') 'A',
           mean(credit = 'B') 'B',
           mean(credit = 'C') 'C'
    FROM have
    GROUP BY class;
quit;

[YiqunDai]

Thank you so much!

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