Relaciones jerárquicas en bases de datos relacionales http://elblogdepicodev.blogspot.com/2013/10/relaciones-jerarquicas-en-bases-de-datos-relacionales.html

nested-ascendientes.sql

select c.id as id
	from Categoria as c, Categoria as p 
	where c.left between p.left and p.right
		and c.id = ?

nested-descendientes.sql

select c.id as id
	from Categoria as c, Categoria as p
	where c.left > p.left and c.right < p.right
		and p.id = ?

no-recursivo-ascendientes.sql

select c10.id as id10, c9.id as id9, c8.id as id8, c7.id as id7, c6.id as id6, c5.id as id5, c4.id as id4, c3.id as id3, c2.id as id2, c1.id as id1
	from categoria c1 
		left join categoria c2 on c2.id = c1.categoria_id
		left join categoria c3 on c3.id = c2.categoria_id
		left join categoria c4 on c4.id = c3.categoria_id
		left join categoria c5 on c5.id = c4.categoria_id
		left join categoria c6 on c6.id = c5.categoria_id
		left join categoria c7 on c7.id = c6.categoria_id
		left join categoria c8 on c8.id = c7.categoria_id
		left join categoria c9 on c9.id = c8.categoria_id
		left join categoria c10 on c10.id = c9.categoria_id
	where c1.id = ?

no-recursivo-descendientes.sql

select c1.id as id1, c2.id as id2, c3.id as id3, c4.id as id4, c5.id as id5, c6.id as id6, c7.id as id7, c8.id as id8, c9.id as id9, c10.id as id10
	from categoria c1
		left join categoria c2 on c2.categoria_id = c1.id
		left join categoria c3 on c3.categoria_id = c2.id
		left join categoria c4 on c4.categoria_id = c3.id
		left join categoria c5 on c5.categoria_id = c4.id
		left join categoria c6 on c6.categoria_id = c5.id
		left join categoria c7 on c7.categoria_id = c6.id
		left join categoria c8 on c8.categoria_id = c7.id
		left join categoria c9 on c9.categoria_id = c8.id
		left join categoria c10 on c10.categoria_id = c9.id
	where c1.id = ?

recursivo-ascendientes.sql

with recursive ascendientes as (
	select id as id
		from Categoria c
		where id = ?
	union all
	select c.id as id
		from ascendientes
		join categoria c on ascendientes.id = c.parent)
select id from ascendientes

recursivo-descendientes.sql

with recursive descendientes as (
	select id as id
	from categoria c
		where id = ?
	union all
	select c.id as id
		from descendientes
		join categoria c on c.parent = descendientes.id)
select id from descencientes

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