Alternate to sql using data step

[PGStats]

Is usubjid a unique key in table adae?

Is usubjid a unique key in table adbmk?

Why is this a left join? The condition anl02fl="Y" will essentially transform it into an inner join.

[RAVI2000]

because I would like to see the subjects from left(adbmk) table alone. usubjid is the unique key for both the datasets.