Because usually the information for the subject of interest are scattered in different datasets, it is common to join the tables to gather all the variables of the subject. There needs to be a common id field with the same data format in all the datasets that need to be merged.
Both dataset A and B have a variable id. Merge statement join the variables from A and B by the id variable in A. All the records and fields from A will be in the merged table and those records with equal id field from B will be added to the records in the merged table.
Caution:
- Make sure id in A is unique
- id field in both A and B should be the same type of field (character or numeric)
- After merging the table, need to check if there is any duplicated information and why.
data merged;
merge A (in =a) B;
by id;
if a;
run;