>UPDATE cAgent ;
>  SET yMonth = dtSum.yMonth ;
>  	FROM cAgent ;
>  	JOIN ;
>		(SELECT SUM(yAmount) AS yMonth, ;
>					iAgentID, MONTH(dDate) AS nMonth, ;
>					Year(dDate) AS nYear ;
>    			FROM cMovs ;
>				GROUP BY iAgentID, nMonth, nYear) dtSum ;
>			ON dtSum.iAgentID = cAgent.iID ;
>                    AND dtSum.nMonth = cAgent.nMonth ;
>                    AND dtSum.nYear  = cAgent.nYear
>