SQL操纵XML的问题

[打酱油的]

  set @val = @resumexml.value('(//Field[@id=1586]/MCAnsID)[1]','nvarchar(max)');   

如何让[@id=1586] 动态化起来? 其中的1586我需要替换成@FieldID.
因为这个ID是个动态值.

  set @val = @resumexml.value('(//Field[@id='+@FieldID+']/MCAnsID)[1]','nvarchar(max)');    

  ---------------------------------------------------------------------------------------

  Declare @FieldID int
  select top 1 @FieldID=FieldID from DM_CustField with(nolock) where AccountId=@AccountID and FieldName='Download Exam Result'
  Declare @xmlString nvarchar(200)

  set @val = @resumexml.value(@xmlString ,'nvarchar(max)'); 

  -----以上两种方法均不行.   

[快溜]

exec('set @val = @resumexml.value(''(//Field[@id='+@FieldID+']/MCAnsID)[1]','nvarchar(max)'')')

[快溜]

exec('set '+@val+' = '+@resumexml+'.value(''(//Field[@id='+@FieldID+']/MCAnsID)[1]','nvarchar(max)'')')

[liangCK]

sql:variable()