mysql difficult query union

I have a table:
id  name
1   home
2   menu
3   contact

second table:
id  name   menu_id
1   menu1  2
2   menu2  2
3   menu3  2

and I need this output:
1   home
2   menu
  1   menu1 2
  2   menu2 2
  3   menu3 2
3   contact

I tried this with a union but I failed. Someone knows wha开发者_如何学Got query to use here? Thanks!

select t1.id, t2.id, t1.name, t2.name
  from t1
  left join t2 on t2.menu_id = t1.id
 order by t1.id, t2.id;

Ok, if you want a dataset exactly like the one you posted, here is the query to do that:

select case
         when t1Id < 0 then null
         else t1Id
       end as t1Id, nullif(t2Id, 0) as t2Id, t1Name, t2Name
  from (
     select id as t1Id, 0 as t2Id, name as t1Name, null as t2Name
       from t1
      union
     select -menu_id as t1Id, id as t2Id, null as t1Name, name as t2Name
       from t2
    ) allTables
  order by abs(allTables.t1Id), abs(allTables.t1Id) * 100 + allTables.t2Id;