I wrote a SQL statement that appeared to be okay, but it has an error:

"SQL: column 'EFF_DATE' is not found".

What did I do wrong? I am trying to not have dupe records. The only way to do that is to get the Maximum Effective Date.

SELECT DISTINCT cv.GrpID, cv.GrpNum, in.Emp_ID, in.LastName, in.FirstName, in.SS_Number, ;
		cv.Eff_Date;
	FROM GRPEXTIN in ;
	JOIN ;
		(SELECT GrpID, GrpNum, MAX(Eff_Date) AS MaxEffDate FROM GRPEXTCV GROUP BY GrpID, GrpNum) cv ;
		ON in.GrpID+in.GrpNum=cv.GrpID+cv.GrpNum  ;
	WHERE cv.Hist ='99' AND ;
		(INLIST(cv.GrpID, "ACS") AND ;
		INLIST(cv.Status, 'A' ,'B') AND ;
		cv.Renewal<>'H') ;
	ORDER BY cv.GrpID, cv.GrpNum ;
	INTO CURSOR tmpResults