把字符里出现_mark的，全部把_mark去掉

 

例子:

      show_smail_img原来的值  /upload/goods/2017/11/27/0a9bc71a56a650341359a85366a9b112_mark_thumb.jpg  替换后 /upload/goods/2017/11/27/0a9bc71a56a650341359a85366a9b112_thumb.jpg

update  idms_goods_pics  set show_smail_img=replace (`show_smail_img`,'_mark','')   where show_smail_img like '%mark%';