字段名=replace(cast(字段名 as varchar(2000)),‘需要被替换字符‘,‘用来替换的字符‘)
where content like ‘%字符%‘
例：
update os_article set content=replace(cast(content as varchar(max)),‘http://www.cnblogs.com/eyren‘,‘http://anniekids.org‘)
where content like ‘%http://www.cnblogs.com/eyren%‘
