MySQL 8.0

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create table tblOrganizationTypes (OrganizationTypeID int, ParentOrganizationTypeID int, Name varchar(100),DateDeleted date);
insert into tblOrganizationTypes values(1,null, 'parent',null);
insert into tblOrganizationTypes values(2,1, 'child 1',null);
insert into tblOrganizationTypes values(3,1, 'child 2',null);
insert into tblOrganizationTypes values(5,null, 'parent 5',null);
SELECT 
    a.OrganizationTypeID,
    b.OrganizationTypeID,
    a.Name ParentName,
    b.Name ChildName,
    CASE
        WHEN b.ParentOrganizationTypeID IS NULL THEN a.Name
        ELSE CONCAT_WS('>', a.Name, b.Name)
    END AS res
FROM
    tblOrganizationTypes a
        left JOIN
    tblOrganizationTypes b ON b.ParentOrganizationTypeID = a.OrganizationTypeID 
    or a.ParentOrganizationTypeID is null
where a.DateDeleted is null and b.OrganizationTypeID is not null
ORDER BY a.OrganizationTypeID , b.OrganizationTypeID


OrganizationTypeID
OrganizationTypeID
ParentName
ChildName
res


1
1
parent
parent
parent

1
2
parent
child 1
parent>child 1

1
3
parent
child 2
parent>child 2

1
5
parent
parent 5
parent

5
1
parent 5
parent
parent 5

5
2
parent 5
child 1
parent 5>child 1

5
3
parent 5
child 2
parent 5>child 2

5
5
parent 5
parent 5
parent 5


select a.OrganizationTypeID
    , a.ParentOrganizationTypeID
    , a.Name
    , a.Name as childname
    , a.Name as res
from tblOrganizationTypes a
where a.ParentOrganizationTypeID is null
  and a.DateDeleted is null 
union all
SELECT 
    a.OrganizationTypeID,
    b.OrganizationTypeID,
    a.Name ParentName,
    b.Name ChildName,
    CONCAT_WS('>', a.Name, b.Name) AS res
FROM tblOrganizationTypes a
JOIN tblOrganizationTypes b 
    ON b.ParentOrganizationTypeID = a.OrganizationTypeID 
where a.DateDeleted is null 
ORDER BY OrganizationTypeID, ParentOrganizationTypeID;


OrganizationTypeID
ParentOrganizationTypeID
Name
childname
res


1
null
parent
parent
parent

1
2
parent
child 1
parent>child 1

1
3
parent
child 2
parent>child 2

5
null
parent 5
parent 5
parent 5

OrganizationTypeID	OrganizationTypeID	ParentName	ChildName	res
1	1	parent	parent	parent
1	2	parent	child 1	parent>child 1
1	3	parent	child 2	parent>child 2
1	5	parent	parent 5	parent
5	1	parent 5	parent	parent 5
5	2	parent 5	child 1	parent 5>child 1
5	3	parent 5	child 2	parent 5>child 2
5	5	parent 5	parent 5	parent 5

OrganizationTypeID	ParentOrganizationTypeID	Name	childname	res
1	null	parent	parent	parent
1	2	parent	child 1	parent>child 1
1	3	parent	child 2	parent>child 2
5	null	parent 5	parent 5	parent 5