SAS MERGE GENERATING ADDITIONAL ROWS (WHY?)

[Benbo123321]

i'm doing the equivalent of a left join in SAS on approximately 32 million rows.  The output contains 7 additional rows compared to the original.  I looked at the USSGL and there seems to be no pattern as to why it generated addtional rows.  Any thoughts?

My code:

DATA WORK.TEST;

MERGE FL_AUG (IN=A) XWALK (IN=B KEEP=USSGL DR_CR_IND);

BY USSGL;

IF (A) THEN OUTPUT;

RUN;

[Astounding]

Have you checked the XWALK data to see if it contains multiple entries for the same USSGL?  That's the most likely culprit.

[PGStats]

If USSGL identifies unique observations in FL_AUG then 

IF A and first.USSGL then output;

should solve the problem.