/*method1*/
data exe1;
input id $ dep $ salary;
cards;
1003 bd .
;
data exe2;
input id $ dep $ salary;
cards;
1001 ac 2100
1003 bd 2900
;
proc sql;
select exe1.id, exe1.dep,exe2.salary
from exe1 left join exe2
on exe1.id=exe2.id
and exe1.dep=exe2.dep;
quit;
/*method2*/
data e1;
input id $ dep $ age ;
cards;
1001 ac 23
1002 ac 25
1001 bk 19
1003 bd 22
;
data e2;
input id $ dep $ salary;
cards;
1001 ac 2300
1002 ac 2500
1001 bk 1900
;
data e3;
input id $ dep $ salary;
cards;
1001 ac 2100
l003 bd 2900
;
proc sql;
create table a as
select e1.id,e1.dep,salary
from e1 left join e2
on e1.id=e2.id
and e1.dep=e2.dep
where salary is not null;
quit;
proc sql;
create table b as
select e1.id,e1.dep,salary
from e1 left join e2
on e1.id=e2.id
and e1.dep=e2.dep
where salary is null;
quit;
proc sql;
select b.id,b.dep,e3.salary
from b left join e3
on b.id=e3.id
and b.dep=e3.dep;
quit;
Can someone help me, why there are two different results from method 1 and method 2?
