Merging by adding rows on repeated data

[asgee]

Hi all,

I have some repeated longitudinal data and I want to merge them by ID. I'm trying to add the additional data as extra rows for that ID. 

Data1

ID	Date	Age
12345	01DEC2020	25
12345	02MAR2021	26
12345	03APR2022	27

Data2

ID	Date	Age	Data_Out	XYZ_Out
12345	01DEC2027	32	YES	0.21
12345	02MAR2028	33	NO	0.99
12345	03APR2029	34	YES	0.64
12345	04AUG2030	35	.	0.85
12345	05DEC2031	36	YES	0.19

What I'd like to create is the table below where rows from Data2 is added on top of Data1 (so that they're in chronological order based on date and age):

ID	Date	Age	Data_Out	XYZ_Out
12345	01DEC2020	25
12345	02MAR2021	26
12345	03APR2022	27
12345	01DEC2027	32	YES	0.21
12345	02MAR2028	33	NO	0.99
12345	03APR2029	34	YES	0.64
12345	04AUG2030	35	.	.
12345	05DEC2031	36	YES	0.19

The code I have right now is not merging the way I'd like as it ends up merging horizontally and duplicates the row data. It also gives me a "WARNING: Multiple lengths were specified for the BY variable Subject by input data sets" error. 

data want;

merge data1 (in=A) data2 (in=B);

by ID;

if A;

run;

Any help with this would be appreciated, thanks.

[ballardw · Accepted solution]

data want;

   set data1

        data2

   ;

run;

And what was in your existing Have data set????? Interaction between more than one SET and/or MERGE statement is not a beginner exercise.

You are appending (stacking) data. SAS MERGE if for sidewise combinations to align additional (usually) variables on the same row with common key values. Though if none of the key values match between the two sets Merge will look the same.

Any time you combine multiple data sets variables of the same name should be made to have the same type (all numeric or all character for common names) or the process will fail. If they have different lengths you will get a message like that and may get data truncated depending on orders of things. (Can't fit 10 letters into a space that is expecting 5).

And usually easier to sort afterwards.