MySQL 8.0

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CREATE TABLE mytable(
   UID        INTEGER  NOT NULL  
  ,Name       VARCHAR(7) NOT NULL
  ,Generation INTEGER  NOT NULL
  ,Parent_UID  INTEGER  NOT NULL
);

INSERT INTO mytable(UID,Name,Generation,Parent_UID) VALUES (1,'Parent1',1,0);
INSERT INTO mytable(UID,Name,Generation,Parent_UID) VALUES (3,'Parent2',1,0);
INSERT INTO mytable(UID,Name,Generation,Parent_UID) VALUES (7,'Parent4',1,0);
INSERT INTO mytable(UID,Name,Generation,Parent_UID) VALUES (14,'Child7',2,3);
INSERT INTO mytable(UID,Name,Generation,Parent_UID) VALUES (17,'Child8',2,3);
INSERT INTO mytable(UID,Name,Generation,Parent_UID) VALUES (20,'Parent8',1,0);
INSERT INTO mytable(UID,Name,Generation,Parent_UID) VALUES (55,'Child9',2,7);
INSERT INTO mytable(UID,Name,Generation,Parent_UID) VALUES (75,'Child12',3,55);
INSERT INTO mytable(UID,Name,Generation,Parent_UID) VALUES (90,'Child40',3,17);
INSERT INTO mytable(UID,Name,Generation,Parent_UID) VALUES (95,'Child20',2,7);
with recursive cte(uid, name, generation, parent_uid, path) as (
	select t.*, cast(lpad(uid, 3, 0) as char(100)) from mytable t where parent_uid = 0
	union all
	select t.*, concat(c.path, '/', lpad(t.uid, 3, 0))
	from cte c
	inner join mytable t on t.parent_uid = c.uid
)
select * from cte order by path


uid
name
generation
parent_uid
path


1
Parent1
1
0
001

3
Parent2
1
0
003

14
Child7
2
3
003/014

17
Child8
2
3
003/017

90
Child40
3
17
003/017/090

7
Parent4
1
0
007

55
Child9
2
7
007/055

75
Child12
3
55
007/055/075

95
Child20
2
7
007/095

20
Parent8
1
0
020

uid	name	generation	parent_uid	path
1	Parent1	1	0	001
3	Parent2	1	0	003
14	Child7	2	3	003/014
17	Child8	2	3	003/017
90	Child40	3	17	003/017/090
7	Parent4	1	0	007
55	Child9	2	7	007/055
75	Child12	3	55	007/055/075
95	Child20	2	7	007/095
20	Parent8	1	0	020