>>CREATE CURSOR vacation (dstart D,dend D)
>>INSERT INTO vacation VALUES (DATE()-3,DATE()+5)
>>
>>returns empty cursor but correct result is date()-4
>
>with a empty vacation, and dbefore=DATE()
>which is the result ?

Result is year 1.1.1960
This result is wrong, must must be date()-1

SET ENGINEBEHAVIOR 90
CREATE CURSOR vacation  (dstart D,dend D)
INSERT INTO vacation  VALUES (DATE()+3,DATE()+5)
dbefore=DATE()
SELECT NVL(MAX(T1.dend)+1,date(1960,1,1)) dFreeMaxFirst ;
	FROM vacation T1 ;
	WHERE dend < m.dbefore;
		AND dend + 1 NOT IN (SELECT dstart FROM vacation);
		 INTO CURSOR result
BROWSE

>If you want the "near before" free day the query is little more complex.

Yes, I want it. The follong code returs 1.1.1960 but must return DATE()-4

SET ENGINEBEHAVIOR 90
CREATE CURSOR vacation  (dstart D,dend D)
INSERT INTO vacation  VALUES (DATE()+3,DATE()+5)

dbefore=DATE()
SELECT NVL(MAX(T1.dend)+1,date(1960,1,1)) dFreeMaxFirst ;
	FROM vacation T1 ;
	WHERE dend < m.dbefore;
		AND dend + 1 NOT IN (SELECT dstart FROM vacation);
		 INTO CURSOR result
BROWSE