中文 length()
英文 lengthb()select decode(length(parent_menu_id),2,menu_id,''), --一级菜单
decode(length(parent_menu_id),4,menu_id,''), --二级菜单
decode(length(parent_menu_id),6,menu_id,'') --三级菜单
from menu
where role_id = ???
英文 lengthb()select decode(length(parent_menu_id),2,menu_id,''), --一级菜单
decode(length(parent_menu_id),4,menu_id,''), --二级菜单
decode(length(parent_menu_id),6,menu_id,'') --三级菜单
from menu
where role_id = ???
4,menu_id, ///二级
6,menu_id, ///三级
'') from menu