mysql - Order row selection by multiple columns

Question

I have a database

id    |     parentid     |       name
1     |        0         |      CatOne
2     |        0         |      CatTwo
3     |        0         |      CatThree
4     |        1         |      SubCatOne
5     |        1         |      SubCatOne2
6     |        3         |      SubCatThree

How I can select this cats Order By id, parentid? That is

CatOne 1
--SubCatOne 4
--SubCatOne2 5
CatTwo 2
CatThree 3
--SubCatThree 6

Answer 1

assuming your table is named cats, try this:

select * from  cats
order by
      case when parentid = 0 then id else parentid end,
      case when parentid = 0 then 0 else id end

Updated to include when parent would have higher id compared to the children