merging data sets

[mona4u]

I'm trying to merge two data sets and I can't get the result that I want 

this is my code 

proc sort data=vwr2 out=vwr3; by protocol protocol1; run;
proc sort data=pqr2 out=pqr3; by protocol; run;

data mmm;
merge pqr3 vwr3;
by protocol;
run;

this is the two datasets and the result

Obs	Protocol_No	visit_status	Workflow_Status	protocol	protocol1
1	A3921104	Locked	Complete	1104	1104
2	A3921104	Locked	Complete	1104	1104
Obs	Site_Number	Category	protocol
1	A3921104 1079	Other	1104
2	A3921104 1079	Other	1104
3	A3921104 1079	Other	1104
4	A3921104 1079	Other	1104
5	A3921104 1079	Other	1104
6	A3921104 1134	Other	1104
7	A3921104 1134	Other	1104
8	A3921104 1134	Other	1104
Obs	Site_Number	Category	protocol	Protocol_No	visit_status	Workflow_Status	protocol1
1	A3921104 1079	Other	1104	A3921104	Locked	Complete	1104
2	A3921104 1079	Other	1104	A3921104	Locked	Complete	1104
3	A3921104 1079	Other	1104	A3921104	Locked	Complete	1104
4	A3921104 1079	Other	1104	A3921104	Locked	Complete	1104
5	A3921104 1079	Other	1104	A3921104	Locked	Complete	1104
6	A3921104 1134	Other	1104	A3921104	Locked	Complete	1104
7	A3921104 1134	Other	1104	A3921104	Locked	Complete	1104
8	A3921104 1134	Other	1104	A3921104	Locked	Complete	1104

this the my aimed result 

Obs	Site_Number	Category	protocol	Protocol_No	visit_status	Workflow_Status	protocol1
1	A3921104 1079	Other	1104	A3921104	Locked	Complete	1104
2	A3921104 1079	Other	1104	A3921104	Locked	Complete	1104
3	A3921104 1079	Other	1104	.	.	.	.
4	A3921104 1079	Other	1104	.	.	.	.
5	A3921104 1079	Other	1104	.	.	.	.
6	A3921104 1134	Other	1104	.	.	.	.
7	A3921104 1134	Other	1104	.	.	.	.
8	A3921104 1134	Other	1104	.	.	.	.

[Astounding]

While I'm not sure I can justify your intended result, you want what you want.  So here's an easy way:

data mmm;
merge pqr3 vwr3;
by protocol;

output;

call missing(Protocol_No);

call missing(visit_status);

call missing(Workflow_Status);

call missing(protocol1);
run;

[SuryaKiran]

By what logic are you making the values missing even they have matching id's for a merge.

[Ksharp]

data mmm;
inb=0;
merge pqr3 vwr3(in=inb rename=(protocol=protocol1));
by protocol;
if not inb then call missing(visit_status,workflow,protocol1);
run;