Its not often I can out do Larry <g>:

LPARAMETER tdTarget

m.tdTarget = IIF(VARTYPE(m.tdTarget) = "D" AND NOT EMPTY(m.tdTarget), tdTarget, CTOD("04/01/2001")

SELECT * ;
FROM Stest St1 ;
WHERE code + TRANSFORM(Date) IN ;
(SELECT code + TRANSFORM(MIN(Date)) ;
FROM Stest S2 ;
GROUP BY Code ;
HAVING MONTH(MIN(SDate)) = m.tdTarget)

Regards,
Thom C.