UPDATE amaster
		SET cmdb = cmdb + transact.damt, cmcr = cmcr + transact.camt
	FROM amaster
	JOIN transact ON transact.acctno = amaster.acctno

>sorry i post the a wrong statement,
>
>UPDATE amaster
>SET cmdb = amaster.cmdb + transact.damt, cmcr = amaster.cmcr + transact.camt
>FROM transact CROSS JOIN
> amaster
>WHERE (transact.acctno = amaster.acctno)
>
>
>what trying to do is update the field on the file with old value added new value to it