DatasetA:
CustomerID     HouseholdID   EmailAddress  ...
1001            100001         joe@aol.com
1002            100002         john@gmail.com
2003            100003         sally@comcast.net

DatasetB:
HouseholdID
100003
100001

Desired Output (DatasetC)
CustomerID    HouseholdID   EmailAddress ... DatasetBHouseholdID
1001          100001        joe@aol.com       100001
1002          100002        john@gmail.com    .
2003          100003        sally@comcast.net 100003
...

data data.datasetc;
merge data.dataseta data.datasetb (RENAME=(householdID=datasetbhouseholdID));
by householdid;
run;

DatasetB:
HouseholdID     DatasetBHouseholdID
100003            100003
100001            100001