SET @ROOMLIST = '<RoomList>
           <Root xmlns="http://zzz.yyy.com">
             <RoomInfo>
                <AdultNum>2</AdultNum>
                <ChildNum>2</ChildNum>
                <ChildAges>
                   <ChildAge age="1"/>
                  <ChildAge age="12"/>
                </ChildAges>
             </RoomInfo>
          </Root>
      </RoomList>'

DECLARE @rt TABLE (roomno INT, Can_Adl INT, Can_Chd INT, ChildAges XML)

;WITH XMLNAMESPACES(DEFAULT 'http://zzz.yyy.com')
    INSERT INTO @rt (Can_Adl, Can_Chd, ChildAges)
        SELECT
            r.value('(AdultNum/text())[1]', 'int') AS CAN_ADL,
            r.value('(ChildNum/text())[1]','int') AS CAN_CHD,
            r.query('ChildAges') AS ChildAges
        FROM
            @ROOMLIST.nodes('//RoomInfo') AS t(r)
        OUTER APPLY
            (SELECT t.r.query('ChildAges') AS c) qlo

<p1:ChildAges xmlns:p1="http://zzz.yyy.com">
   <p1:ChildAge age="1" />
   <p1:ChildAge age="12" />
</p1:ChildAges>