SQL : Sum by criteria - sql

Question

I'm working with Oracle and cannot achieve the query I need for the moment.
Suppose I have the following table :
- ID Date Type Value
- 1 01/12/2016 prod 1
- 2 01/01/2017 test 10
- 3 01/06/2017 test 20
- 4 01/12/2017 prod 30
- 5 15/12/2017 test 40
- 6 01/01/2018 test 50
- 7 01/06/2018 test 60
- 8 01/12/2018 prod 70
I need to sum the VALUES between the "prod" TYPES + the last "prod" VALUE.
The results should be :
- 1 01/01/2016 - 1
- 2 01/01/2017 - 60
- 3 01/06/2017 - 60
- 4 01/12/2017 - 60
- 5 15/12/2017 - 220
- 6 01/01/2018 - 220
- 7 01/06/2018 - 220
- 8 01/12/2018 - 220
I first had to sum VALUES by YEAR without taking TYPES into account.
The need changed and I don't see how to start to identify, for each line, which is the previous "prod" DATE and sum each VALUE including the last "prod" TYPE.
Thanks

Answer 1

You can define the groups using a cumulative sum on type = 'PROD' -- in reverse, then use a window function for the final summation:
select t.*,
sum(value) over (partition by grp) as total
from (select t.*,
sum(case when type = 'PROD' then 1 else 0 end) over (order by id desc) as grp
from t
) t
order by id;
To see the grouping logic, look at:
ID Date Type Value Grp
1 01/12/2016 prod 1 3
2 01/01/2017 test 10 2
3 01/06/2017 test 20 2
4 01/12/2017 prod 30 2
5 15/12/2017 test 40 1
6 01/01/2018 test 50 1
7 01/06/2018 test 60 1
8 01/12/2018 prod 70 1
This identifies the groups that need to be summed. The DESC is because "prod" ends a group. If "prod" started a group (i.e. was included with the sum on the next row), then ASC would be used.
Rextester Demo

Answer 2

Gordon Linoff's answer is great.
This below is just for a bit of a different flavor(12c+)
Setup:
ALTER SESSION SET NLS_DATE_FORMAT = 'DD/MM/YYYY';
CREATE TABLE TEST_TABLE(
THE_ID INTEGER,
THE_DATE DATE,
THE_TYPE CHAR(4),
THE_VALUE INTEGER);
INSERT INTO TEST_TABLE VALUES (1,TO_DATE('01/12/2016'),'prod',1);
INSERT INTO TEST_TABLE VALUES (2,TO_DATE('01/01/2017'),'test',10);
INSERT INTO TEST_TABLE VALUES (3,TO_DATE('01/06/2017'),'test',20);
INSERT INTO TEST_TABLE VALUES (4,TO_DATE('01/12/2017'),'prod',30);
INSERT INTO TEST_TABLE VALUES (5,TO_DATE('15/12/2017'),'test',40);
INSERT INTO TEST_TABLE VALUES (6,TO_DATE('01/01/2018'),'test',50);
INSERT INTO TEST_TABLE VALUES (7,TO_DATE('01/06/2018'),'test',70);
INSERT INTO TEST_TABLE VALUES (8,TO_DATE('01/12/2018'),'prod',60);
COMMIT;
Query:
SELECT
THE_ID, THE_DATE, MAX(RUNNING_GROUP_SUM) OVER (PARTITION BY THE_MATCH_NUMBER) AS GROUP_SUM
FROM TEST_TABLE
MATCH_RECOGNIZE (
ORDER BY THE_ID
MEASURES
MATCH_NUMBER() AS THE_MATCH_NUMBER,
RUNNING SUM(THE_VALUE) AS RUNNING_GROUP_SUM
ALL ROWS PER MATCH
AFTER MATCH SKIP PAST LAST ROW
PATTERN (TEST_TARGET{0,} PROD_TARGET)
DEFINE TEST_TARGET AS THE_TYPE = 'test',
PROD_TARGET AS THE_TYPE = 'prod')
ORDER BY THE_ID ASC;
Result:
THE_ID THE_DATE GROUP_SUM
---------- ---------- ----------
1 01/12/2016 1
2 01/01/2017 60
3 01/06/2017 60
4 01/12/2017 60
5 15/12/2017 220
6 01/01/2018 220
7 01/06/2018 220
8 01/12/2018 220