Try

SELECT Num1 + Num2 FROM mytable ;
	WHERE Num1 + Num2 IN ;
		(select Num2+Num1 from mytable ) ;
UNION ;
SELECT Num1 + Num2 FROM mytable ;
	WHERE Num2 + Num1 IN ;
		(select Num1+Num2 from mytable ) ;
	INTO CURSOR crsList	

DELETE FROM mytable ;
	WHERE num1+num2 in ( ;
		SELECT Num1+Num2 FROM crsList)

> Do I need to input ?nValue each time to delete ? the fact I have thousand
>mutual records to delete in one single process .