Merging the data sets using macro code

Merging the data sets with a common variable if the datasets has the same prefix name?

For example: col1-col10 dsn1-dsn 7 data1 to data6 with common variable of Usubjid.

here is the example, I have 7 datasets i need to merge and each of them having the common variable(usubjid) to merge, and all the datasets having the same prefix dsn(dsn1 to dsn7).

%macro allmerge (n);
data combine;
merge
%do i = 1 % to &n;
dsn&i
%end;
; /* this additional ';' is necessary, the first ';' is for
the "%end", while the second ';' is for "Merge" */
by usubjid;
run;
%mend;
%allmerge (7)