select menu_id,menu_name,Father_Id from Sys_Menu where menu_id='18' or Father_Id=18 or -- 一级、二级 Father_Id in (select menu_id from Sys_Menu a where menu_id='18' or Father_Id=18) or -- 三级 father_id in (select menu_id from sys_menu where Father_Id in (select menu_id from Sys_Menu a where menu_id='18' or Father_Id=18)) -- 四级
select menu_id,menu_name,Father_Id from Sys_Menu where menu_id='18' or Father_Id=18 or -- 一级、二级
Father_Id in (select menu_id from Sys_Menu a where menu_id='18' or Father_Id=18) or -- 三级
father_id in (select menu_id from sys_menu where Father_Id in (select menu_id from Sys_Menu a where menu_id='18' or Father_Id=18)) -- 四级