>Both are characters.
>
>I have sample data on both tables with no matching records. But when I run the code, it results to 200+ records.

Evelyn,

As Gregory pointed out, you made a typo in the JOIN condition - you used the same table twice on both side of expression, therefore you got a cartesian join.

You need to join on

SELECT * FROM mds ;
INNER JOIN acic ;
ON acic.checkno = mds.checkno and acic.acctno = mds.acctno ;
INTO CURSOR csr_Match