>No, it will not work. You can not use GROUP BY and relate the fields, AFAIK.

I am sure you can, what I am not sure if it yields the right results as I might have misunderstood the original SELECT, try running the statement yourself and you'll not get an error (EngineBehaviur 90)

CREATE CURSOR table1 (setid I, deptid I, effd T)
CREATE CURSOR table2 (setid I, deptid I, effdt T)

INSERT INTO table1 VALUES (1, 1, DATE() - 2)
INSERT INTO table1 VALUES (1, 2, DATE() - 2)

INSERT INTO table2 Values(1, 1, DATE() - 4)
INSERT INTO table2 Values(1, 1, DATE() - 3)
INSERT INTO table2 Values(1, 1, DATE() - 2)
INSERT INTO table2 Values(1, 1, DATE() - 1)
INSERT INTO table2 Values(1, 1, DATE() - 0)


SELECT		Table1.*, ;
		A.*, ;
		Table2.* ;
	FROM	Table1 ;
	LEFT	OUTER JOIN	( ;
				SELECT		MAX(B.effdt) as maxeffdt, ;
						B.SetID, ;
						B.DeptID ;
					FROM	Table2 B ;
					WHERE	B.effdt < Table1.effd ;
					GROUP	BY B.SetID, B.DeptID ;
			) A ON Table1.setid = A.setid AND Table1.deptid = A.deptid ;
	LEFT	OUTER JOIN Table2 ON Table1.setid = Table2.setid AND Table1.deptid = Table2.deptid AND Table2.effdt = A.maxeffdt