How to keep related groups together? - postgresql

Question

DB fiddle DB fiddle (updated)
I pay attention to 1-2; 3-4 cases. Notice, that all rows from config_id group still together with all rows of xgroup
Detailed task description:
I have some order details for some resource. For each ordered resource there should be allocated resource. Resource may belongs to each other and belongs to some group. Consider virtual machine VM has: RAM, CPU, HDD.
Currently relation between orders and allocated resources is broken. I try to write query to analyze what is ordered without allocated resource and what is allocated without order.
CREATE TABLE order_detail (
id SERIAL,
order_id INTEGER,
resource_type_id INTEGER,
allocated_resource_id INTEGER,
amount INTEGER
)
CREATE TABLE allocated_resource (
id SERIAL,
group_id INTEGER,
resource_type_id INTEGER,
resource_uuid UUID,
)
This is easily done:
select * from order_detail od
where od.allocated_resource_id IS NULL
SELECT * FROM allocated_resource ar
WHERE NOT EXISTS ( SELECT 1 FROM order_detail od where od.allocated_resource_id = ar.id)
But I need to found to which Order assign that allocated resource. Or which resource allocate for this Order. Or which Order bind to allocated resource.
Data example:
id | order_id | allocated_resource_id | resource_type_id
--------------------------------------------------------
41 | 1 | 1 | 70
42 | 1 | | 71
43 | 1 | | 73
44 | 2 | | 70
45 | 2 | 5 | 71
id | group_id | resource_type_id
--------------------------------
1 | 1 | 70
2 | 1 | 71
3 | 1 | 72
4 | 2 | 70
5 | 2 | 71
6 | 2 | 73
Here I want to get:
id | order_id | allocated_resource_id | resource_type_id | ar.id | ar.group_id | ar.resource_type_id
----------------------------------------------------------------------------------------------------
41 | 1 | 1 | 70 | 1 | 1 | 70
42 | 1 | | 71 |
43 | 1 | | 73 |
| | | | 1 | 1 | 71
| | | | 1 | 1 | 72
44 | 2 | | 70 |
45 | 2 | 5 | 71 | 5 | 1 | 71
| | | | 4 | 1 | 70
| | | | 6 | 1 | 73
Unfortunately order by ar.id or order by od.id will move unbound order details/allocated resource to bottom. I want to keep order details/allocated resources together as in example above.
To resolve task I select all available related groups first:
od_ar_group AS (
SELECT
od.order_id, ar.group_id,
cast( od.order_id AS TEXT ) || '-' || cast( ar.group_id AS TEXT ) AS odar
FROM order_detail od
FULL JOIN allocated_resource ar ON ar.id = od.allocated_resource_id
WHERE od.order_id IS NOT NULL AND ar.group_id IS NOT NULL
GROUP BY od.order_id, ar.group_id
)
Then I attach group info to both tables:
SELECT od.*, odar.odar
FROM order_detail od
LEFT JOIN od_ar_group odar ON odar.order_id = od.order_id
SELECT ar.*, odar.odar
FROM allocated_resource ar
LEFT JOIN od_ar_group odar ON odar.parent_id = ar.parent_id
Finally I can join those groups and sort inside them. So unbound order detail/allocated resource is inside group and not at the bottom of table:
SELECT
CASE WHEN od.odar IS NOT NULL THEN od.odar ELSE ar.odar END AS odar,
od.*, ar.*
FROM od_grouped
FULL JOIN ar_grouped ar ON ar.odar = od.odar
AND ar.id = od.allocated_resource_id
ORDER BY odar, CASE WHEN od.id IS NULL THEN 1 WHEN ar.id IS NULL THEN 2 ELSE 0 END, od.id NULLS LAST
Is there a more easy way to keep related rows inside their group?