Hierarchical sum of the columns in oracle - sql

Question

I have got one problem as follows:
ID NAME AMOUNT PARENTID
1 Adam 1000 0
2 John 2000 1
3 Clark 1500 2
4 Rita 1200 3
5 jack 1600 3
6 mark 1800 2
7 Finn 1500 6
8 Ryan 1100 6
So the data above is the result of a query with multiple joins
and it is a kind of hierarchy or tree something like this:
1
|
2
/ \
3 6
/ \ / \
5 4 7 8
and now I need to modify my query so that I get the following result
ID NAME AMOUNT PARENTID DownstreamSum
1 Adam 1000 0 10700
2 John 2000 1 8700
3 Clark 1500 2 2800
4 Rita 1200 3 0
5 jack 1600 3 0
6 mark 1800 2 2600
7 Finn 1500 6 0
8 Ryan 1100 6 0
So the logic is that the parent should have the sum of all the downstream child nodes in the DownstreamSum column.
for example:
id 6 should have the sum of amount of id 7 and 8
id 3 should have the sum of amount of id 4 and 5
but id 2 should have the sum of the amount of id 3 and the sum of amount of id 4 and 5
I tried with many possibilities with partition by and group by but I was not able to get the desired output.

Answer 1

Here is the query, please check.
SQL fiddle link
SELECT Y.*, X.TOTAL_AMOUNT FROM (
WITH hierarchy (PARENTID, ID) AS (SELECT PARENTID, ID
FROM Hierarchy_result
UNION ALL
SELECT h.PARENTID, bs.ID
FROM Hierarchy_result bs, hierarchy h WHERE bs.PARENTID=h.ID)
SELECT h.PARENTID AS PARENTID,
--SUM(FR.AMOUNT)
/*SUM((CASE WHEN FR.ID=h.PARENTID
THEN FR.amount
ELSE 0.0 END))*/
SUM(FR.amount) TOTAL_AMOUNT
FROM hierarchy h, Hierarchy_result FR WHERE FR.ID=h.ID
GROUP BY h.PARENTID
ORDER BY h.PARENTID) X, Hierarchy_result Y WHERE X.PARENTID(+) = Y.ID ORDER BY Y.ID;

Answer 2

A typical recursive CTE (available since Oracle 11gR2) will allow you to walk the branches to the leaves. Then a simple SUM() gives you the result you want. For example:
with
n (root_id, current_id, name, amount, parentid) as (
select id, id, name, amount, parentid from t
union all
select n.root_id, t.id, t.name, t.amount, t.parentid
from n
join t on t.parentid = n.current_id
)
select t.id, t.name, t.amount, t.parentid,
sum(n.amount) - t.amount as downstreamsum
from t
join n on n.root_id = t.id
group by t.id, t.name, t.amount, t.parentid
order by t.id
Result:
ID NAME AMOUNT PARENTID DOWNSTREAMSUM
--- ------ ------- --------- -------------
1 Adam 1000 0 10700
2 John 2000 1 8700
3 Clark 1500 2 2800
4 Rita 1200 3 0
5 jack 1600 3 0
6 mark 1800 2 2600
7 Finn 1500 6 0
8 Ryan 1100 6 0
See running example at db<>fiddle.

Answer 3

This query also calculates own and child sums and count:
with mcnt (
id, parentid, name, amount
,rnk
,level_members_cnt
,level_members_sum
,own_members_cnt
,own_members_sum
,child_members_cnt
,child_members_sum
) as (
select
p.id, p.parentid, p.name, p.amount
, row_number()over(partition by p.parentid order by p.id) rnk
, sum((select count(*) from Hierarchy_result m where m.parentid=p.id))over(partition by p.parentid) as level_members_cnt
, sum((select sum(m.amount) from Hierarchy_result m where m.parentid=p.id))over(partition by p.parentid) as level_members_sum
, (select count(*) from Hierarchy_result m where m.parentid=p.id) as own_members_cnt
, (select nvl(sum(m.amount),0) from Hierarchy_result m where m.parentid=p.id) as own_members_sum
, 0 as child_members_cnt
, 0 as child_members_sum
from Hierarchy_result p
where not exists(select null from Hierarchy_result child where p.id = child.parentid)
union all
select p.id, p.parentid, p.name, p.amount
, row_number()over(partition by p.parentid order by p.id) rnk
, sum((select count(*) from Hierarchy_result m where m.parentid=p.id))over(partition by p.parentid) level_members_cnt
, sum((select sum(m.amount) from Hierarchy_result m where m.parentid=p.id))over(partition by p.parentid) level_members_sum
, (select count(*) from Hierarchy_result m where m.parentid=p.id) as own_members_cnt
, (select nvl(sum(m.amount),0) from Hierarchy_result m where m.parentid=p.id) as own_members_sum
, mcnt.level_members_cnt + mcnt.child_members_cnt as child_members_cnt
, nvl(mcnt.level_members_sum,0) + nvl(mcnt.child_members_sum,0) as child_members_sum
from mcnt, Hierarchy_result p
where mcnt.parentid=p.id
and mcnt.rnk=1
)
select
id, parentid, name, amount, child_members_cnt, own_members_cnt
,child_members_cnt+own_members_cnt as total_cnt
,child_members_sum,own_members_sum
,child_members_sum+own_members_sum as total_sum
from mcnt
order by id;
Full example with sample data:
with Hierarchy_result ("ID", "NAME", "AMOUNT", "PARENTID") as (
select 1, 'Adam', 1000, 0 from dual union all
select 2, 'John', 2000, 1 from dual union all
select 3, 'Clark', 1500, 2 from dual union all
select 4, 'Rita', 1200, 3 from dual union all
select 5, 'jack', 1600, 3 from dual union all
select 6, 'mark', 1800, 2 from dual union all
select 7, 'Finn', 1500, 6 from dual union all
select 8, 'Ryan', 1100, 6 from dual
)
,mcnt (
id, parentid, name, amount
,rnk
,level_members_cnt
,level_members_sum
,own_members_cnt
,own_members_sum
,child_members_cnt
,child_members_sum
) as (
select
p.id, p.parentid, p.name, p.amount
, row_number()over(partition by p.parentid order by p.id) rnk
, sum((select count(*) from Hierarchy_result m where m.parentid=p.id))over(partition by p.parentid) as level_members_cnt
, sum((select sum(m.amount) from Hierarchy_result m where m.parentid=p.id))over(partition by p.parentid) as level_members_sum
, (select count(*) from Hierarchy_result m where m.parentid=p.id) as own_members_cnt
, (select nvl(sum(m.amount),0) from Hierarchy_result m where m.parentid=p.id) as own_members_sum
, 0 as child_members_cnt
, 0 as child_members_sum
from Hierarchy_result p
where not exists(select null from Hierarchy_result child where p.id = child.parentid)
union all
select p.id, p.parentid, p.name, p.amount
, row_number()over(partition by p.parentid order by p.id) rnk
, sum((select count(*) from Hierarchy_result m where m.parentid=p.id))over(partition by p.parentid) level_members_cnt
, sum((select sum(m.amount) from Hierarchy_result m where m.parentid=p.id))over(partition by p.parentid) level_members_sum
, (select count(*) from Hierarchy_result m where m.parentid=p.id) as own_members_cnt
, (select nvl(sum(m.amount),0) from Hierarchy_result m where m.parentid=p.id) as own_members_sum
, mcnt.level_members_cnt + mcnt.child_members_cnt as child_members_cnt
, nvl(mcnt.level_members_sum,0) + nvl(mcnt.child_members_sum,0) as child_members_sum
from mcnt, Hierarchy_result p
where mcnt.parentid=p.id
and mcnt.rnk=1
)
select
id, parentid, name, amount, child_members_cnt, own_members_cnt
,child_members_cnt+own_members_cnt as total_cnt
,child_members_sum,own_members_sum
,child_members_sum+own_members_sum as total_sum
from mcnt
order by id;
Result
ID PARENTID NAME CHILD_MEMBERS_SUM OWN_MEMBERS_SUM TOTAL_SUM CHILD_MEMBERS_CNT OWN_MEMBERS_CNT TOTAL_CNT
--- -------- ----- ----------------- --------------- ---------- ----------------- --------------- ----------
1 0 Adam 8700 2000 10700 6 1 7
2 1 John 5400 3300 8700 4 2 6
3 2 Clark 0 2800 2800 0 2 2
4 3 Rita 0 0 0 0 0 0
5 3 jack 0 0 0 0 0 0
6 2 mark 0 2600 2600 0 2 2
7 6 Finn 0 0 0 0 0 0
8 6 Ryan 0 0 0 0 0 0
ps. based on my another solution: Hierarchical Query - Counting records that belongs to Parent and Child Places