select * ,replace(NewsContent,'src=','修改后的内容') as rep from News where id=337
update News set NewsContent=replace(cast(NewsContent as varchar(max)),'src="','src="http:') where id=(select NewsTitle,NewsContent from news where ID='337')
select * ,replace(NewsContent,'src=','修改后的内容') as rep from News where id=337
update News set NewsContent=replace(cast(NewsContent as varchar(max)),'src="','src="http:') where id=(select NewsTitle,NewsContent from news where ID='337')