I have these 6 tables and query which returns everything I want, but I want to add a new pivot table, so I can get a list of rows linked to it.
Query:
SELECT DISTINCT ON (pg.id, p.prod_id)
pg.group_name, p.name AS prod_name, v.version,
COALESCE((select default_something from version_child where version_id = v.id),
(select default_something from product_child where prod_id = p.prod_id),
(select default_something from product_group_child where group_id = pg.id)
) as something
FROM product_group pg
LEFT JOIN product p ON pg.id = p.group_id
LEFT JOIN version v ON v.prod_id = p.prod_id
ORDER BY pg.id, p.prod_id, v.version DESC;
Product Group Table
id group_name
---------------------------
1 Nice
2 Very Nice
Product table
prod_id name group_id
---------------------------
1 something 2
2 psp3 1
3 bundle1 2
4 bundle2 1
Version Table
version_id prod_id version
---------------------------
1 2 1.0
2 2 1.1
3 3 2.3
4 1 0.1
5 4 0.4
6 1 0.2
Product Group Child Table
pgt_child_id group_id default_something
---------------------------------
1 2 root2
2 1 root1
Product Child table
pt_child_id prod_id default_something
-------------------------------------------
1 2 override2
Version Child Table
v_child_id version_id default_something
-------------------------------------------
1 3 winner
New Pivot Table
p_id. version_id prod_id
----------------------------------
1 3 2
2 3 1
3 5 1
Running the query DBFiddle I get this now:
Group_name prod_name version default_something
-----------------------------------------------------
Nice psp3 1.1 override2
Nice bundle2 0.4 root1
Very Nice something 0.2. root2
Very Nice bundle1 2.3. winner
What I want is like this
Group_name prod_name version default_something ref
-----------------------------------------------------------
Nice psp3 1.1 override2 []
Nice bundle2 0.4 root1 ["something"]
Very Nice something 0.2. root2 []
Very Nice bundle1 2.3. winner ["something", "psp3"]
the ref column can be an array or comma separated string. Basically I need to add new column ref which joins pivot table with product and version table and return an array/comma separated string. Would be really helpful to have a modified dbfiddle to do what I want it to it.
CodePudding user response：
Here's a solution to your riddle:
SELECT DISTINCT ON (pg.id, p.prod_id)
pg.group_name, p.name AS prod_name, v.version
, COALESCE((SELECT default_something FROM version_child WHERE version_id = v.id)
, (SELECT default_something FROM product_child WHERE prod_id = p.prod_id)
, (SELECT default_something FROM product_group_child WHERE group_id = pg.id)
) AS something
, ARRAY(SELECT p1.name
FROM pivot pv
JOIN product p1 USING (prod_id)
WHERE pv.version_id = v.id
) AS ref
FROM product_group pg
LEFT JOIN product p ON pg.id = p.group_id
LEFT JOIN version v ON v.prod_id = p.prod_id
ORDER BY pg.id, p.prod_id, v.version DESC;
(Rather than an answer to a question.)
db<>fiddle here
Related:
Alternatively, you could use a LATERAL subquery: