ORACLE SQL : SUM in first row with condition - sql

Question

I'm struggling to obtain the following results in a query
Here is my table
Line_num
Line_typ
Cost
1000
6
0
2000
7
5000
3000
7
3000
4000
7
2000
5000
6
0
6000
9
3000
7000
7
2000
8000
1
2000
What I want as result is this
Line_num
Line_typ
Cost
1000
6
10000 (0+5000+3000+2000)
5000
6
5000 (0+3000+2000)
8000
1
2000
Basically to display only rows with line_typ in (6,1) but sum the column costs of all other lines in between.
Thank you for your ideas and help !!
Ivan

Answer 1

The reason Tim Biegeleisen's answer is excellent, but needs some intermediate products and oracle features, can be seen when one uses minimal SQL:
Select line_typ in (1, 6), order by line_num.
Sum the cost for second run over the table with larger line_num n, but
where (third run) there is no line_typ in (1, 6) before n.
Basic complexity O(N³), with indices a bit less.
So:
select h.line_num, h.line_typ,
(select sum(cost)
from tbl g
where g.line_num >= h.line_num
and not exists (select *
from tbl
where line_num > h.line_num
and line_typ in (1, 6)
and line_num <= g.line_num)
) as cost
from tbl h
where h.line_typ in (1, 6)
order by h.line_num
(Given for non-oracle searchers.)
Here is a link to a working demo.

Answer 2

This is a play on a gaps and islands problem. Each island begins upon encountering a Line_typ value of 1 or 6, and ends right before a record containing another 1 or 6 value. We can use COUNT() as an analytic function to find the groups, then report the sums of cost.
WITH cte AS (
SELECT t.*, CASE WHEN Line_typ IN (1, 6) THEN 1 ELSE 0 END AS flag
FROM yourTable t
),
cte2 AS (
SELECT t.*, SUM(flag) OVER (ORDER BY Line_num) AS grp
FROM cte t
),
cte3 AS (
SELECT t.*, MIN(Line_num) OVER (PARTITION BY grp) AS Min_Line_num
FROM cte2 t
)
SELECT MIN(Line_num) AS Line_num,
MAX(CASE WHEN Line_num = Min_Line_num THEN Line_typ END) AS Line_typ,
SUM(Cost) AS Cost
FROM cte3 t
GROUP BY grp
ORDER BY MIN(t.Line_num);
Demo

Answer 3

From Oracle 12, you can use MATCH_RECOGNIZE to perform row-by-row pattern matching:
SELECT *
FROM table_name
MATCH_RECOGNIZE(
ORDER BY line_num
MEASURES
FIRST(line_num) AS line_num,
FIRST(line_typ) AS line_typ,
SUM(cost) AS total_cost
PATTERN (match_type other_type*)
DEFINE
match_type AS line_typ IN (6, 1),
other_type AS line_typ NOT IN (6, 1)
)
Which, for the sample data:
CREATE TABLE table_name (line_num, line_typ, cost) AS
SELECT 1000, 6, 0 FROM DUAL UNION ALL
SELECT 2000, 7, 5000 FROM DUAL UNION ALL
SELECT 3000, 7, 3000 FROM DUAL UNION ALL
SELECT 4000, 7, 2000 FROM DUAL UNION ALL
SELECT 5000, 6, 0 FROM DUAL UNION ALL
SELECT 6000, 9, 3000 FROM DUAL UNION ALL
SELECT 7000, 7, 2000 FROM DUAL UNION ALL
SELECT 8000, 1, 2000 FROM DUAL;
Outputs:
LINE_NUM
LINE_TYP
TOTAL_COST
1000
6
10000
5000
6
5000
8000
1
2000
db<>fiddle here