How do I retrieve releated models from subquery - sql

Question

I have a table with models. Model can be parent to another model (1 to 1)
type Model struct {
ID uuid.UUID`
Name string
ParentModel Model
CaseID uuid.UUID
ProjectID uuid.UUID
ChildModels []Model
}
What I am trying to achive is:
select all models with the same caseID and select all models with caseId from parantModel and childrenModels.
Is it possible with subquery?
I have tried to select with preload (parent/children) with orm, but do not really get where to go from there

Answer 1

Sample data:
CREATE TABLE public.model (
id int4 NOT NULL,
caption varchar NULL,
parent_id int4 NULL,
CONSTRAINT model_pk PRIMARY KEY (id)
);
INSERT INTO model (id, caption, parent_id) VALUES(1, 'Model1', NULL);
INSERT INTO model (id, caption, parent_id) VALUES(2, 'Model2', NULL);
INSERT INTO model (id, caption, parent_id) VALUES(3, 'Model3', NULL);
INSERT INTO model (id, caption, parent_id) VALUES(4, 'Model4', NULL);
INSERT INTO model (id, caption, parent_id) VALUES(5, 'Model1_1', 1);
INSERT INTO model (id, caption, parent_id) VALUES(6, 'Model1_2', 1);
INSERT INTO model (id, caption, parent_id) VALUES(7, 'Model1_3', 1);
INSERT INTO model (id, caption, parent_id) VALUES(8, 'Model1_2_1', 6);
INSERT INTO model (id, caption, parent_id) VALUES(9, 'Model1_2_2', 6);
INSERT INTO model (id, caption, parent_id) VALUES(10, 'Model4_1', 4);
Recursive Query example:
with recursive tbl(id, caption, parent_id) as (
select * from model
where id = 1
union all
select model.* from model
inner join tbl on tbl.id = model.parent_id
)
select * from tbl
Result:
id caption parent_id
1 Model1 [NULL]
5 Model1_1 1
6 Model1_2 1
7 Model1_3 1
8 Model1_2_1 6
9 Model1_2_2 6