The correct (working) way to do that

UPDATE mytable ;
		SET myfld1 = (SELECT MAX(myfld1) FROM mytable WHERE Pk = nPkValue)  - nValue1 + nValue2 ;
	WHERE Pk = nPkValue

>How come I didn't think of that? <g> Thank you very much.
>>You can do it in one update
>>
>>

>>UPDATE MYTABLE SET MYFLD1 = MAX(MYFLD1 - nValue1) + nValue2 WHERE Pk = nPkValue
>>

>>>