convert multiple variable dataset into multiple record dataset

[wfung]

I have a repeated measures dataset with mutiple variables (i.e., one variable per wave of data collection; Wave1_score, Wave2_score, Wave3_score). Is there a way to convert the data to multiple records (i.e., one row per data collection). 

Thank you! 

This is an example of what I have now: 

ID	Grade_Wave1	Score_Wave1	Score_Wave2	Score_Wave3
PL240812G1	5	5	8	7
PL240812G2	4	5	8	9
PL240813G1	5	5	8	8
PL240815G1	6	5	8	9
PL240817G1	7	5	9	9

I want to convert the data to this: 

ID	School	Grade_Wave1	Score_Wave123	Wave
PL240812G1	1	5	5	1
PL240812G1	1	5	8	2
PL240812G1	1	5	7	3
PL240812G2	1	4	5	1
PL240812G2	1	4	8	2
PL240812G2	1	4	9	3
PL240813G1	2	5	5	1
PL240813G1	2	5	8	2
PL240813G1	2	5	8	3
PL240815G1	2	6	5	1
PL240815G1	2	6	8	2
PL240815G1	2	6	9	3
PL240817G1	3	7	5	1
PL240817G1	3	7	9	2
PL240817G1	3	7	9	3

[Astounding]

Assuming that SCHOOL is actually part of your data set, here's a way:

data want;

set have;

array scores {3} score_wave1 - score_wave3;

do wave=1 to 3;

   score_wave123 = scores{wave};

   output;

end;

drop score_wave1 - score_wave3;

run;