update   `dede_art` set title=replace(title,' <IMG border=0 src=Images/hot.gif>','');

update '表名(比如我案例中的dede_art)' set 要修改字段名 = replace (要修改字段名,'被替换的特定字符','替换成的字符')

SELECT * FROM `supe_spaceitems` where `subject` like '%狐狸天空%'

update `supe_spaceitems` set subject=replace(subject,' - 狐狸天空','');