Oracle sql split up rows to fill maxquantity - sql

Question

say i have a list of articles, which i want to split to fill maxvalues:
id | name | quantity | maxquantity
1 | name_a| 3 | 5
2 | name_a| 1 | 5
3 | name_a| 3 | 5
4 | name_a| 5 | 5
5 | name_b| 7 | 4
6 | name_b| 2 | 4
i want to create packages grouped by name, filled up to the maxvalues to get the following results:
id | name | quantity | maxquantity | tag | effective_quantity
1 | name_a| 3 | 5 | name_a_part1 | 3
2 | name_a| 1 | 5 | name_a_part1 | 1
3 | name_a| 3 | 5 | name_a_part1 | 1
^- sum() = maxquantity
3 | name_a| 3 | 5 | name_a_part2 | 2
4 | name_a| 5 | 5 | name_a_part2 | 3
^- sum() = maxquantity
4 | name_a| 5 | 5 | name_a_part3 | 2
^- sum() = maxquantity or the rest of name_a
5 | name_b| 7 | 4 | name_b_part1 | 4
^- sum() = maxquantity
5 | name_b| 7 | 4 | name_b_part2 | 3
6 | name_b| 2 | 4 | name_b_part2 | 1
^- sum() = maxquantity
6 | name_b| 2 | 4 | name_b_part3 | 1
^- sum() = maxquantity or the rest of name_b

Answer 1

One pretty simple method is to explode the data into a separate row for each item, calculate the bins at that level, and then reaggregate:
with cte (id, name, quantity, maxquantity, n) as (
select id, name, quantity, maxquantity, 1 as n
from t
union all
select id, name, quantity, maxquantity, n + 1
from cte
where n < quantity
)
select id, name, quantity, maxquantity,
count(*) as number_in_bin,
ceil(bin_counter / maxquantity) as bin_number
from (select cte.*,
row_number() over (partition by name order by id, n) as bin_counter
from cte
) cte
group by id, name, quantity, maxquantity, ceil(bin_counter / maxquantity)
order by id, bin_number;
Here is a db<>fiddle.

Answer 2

You can do it with a single recursive query using analytic functions:
WITH split_bins (id, name, quantity, maxquantity, tag, effective_quantity, prev_quantity) AS (
SELECT id,
name,
quantity,
maxquantity,
FLOOR(
COALESCE(
SUM(quantity) OVER (
PARTITION BY name
ORDER BY id
ROWS BETWEEN UNBOUNDED PRECEDING AND 1 PRECEDING
),
0
)
/ maxquantity
) + 1,
LEAST(
maxquantity
- MOD(
COALESCE(
SUM(quantity) OVER (
PARTITION BY name
ORDER BY id
ROWS BETWEEN UNBOUNDED PRECEDING AND 1 PRECEDING
),
0
),
maxquantity
),
quantity
),
0
FROM articles
UNION ALL
SELECT id,
name,
quantity,
maxquantity,
tag + 1,
LEAST(
quantity - prev_quantity - effective_quantity,
maxquantity
),
prev_quantity + effective_quantity
FROM split_bins
WHERE prev_quantity + effective_quantity < quantity
)
SEARCH DEPTH FIRST BY id SET id_order
SELECT id,
name,
quantity,
maxquantity,
name || '_part' || tag AS tag,
effective_quantity
FROM split_bins;
Which, for the sample data:
CREATE TABLE articles (id, name, quantity, maxquantity ) AS
SELECT 1, 'name_a', 3, 5 FROM DUAL UNION ALL
SELECT 2, 'name_a', 1, 5 FROM DUAL UNION ALL
SELECT 3, 'name_a', 3, 5 FROM DUAL UNION ALL
SELECT 4, 'name_a', 5, 5 FROM DUAL UNION ALL
SELECT 5, 'name_b', 7, 4 FROM DUAL UNION ALL
SELECT 6, 'name_b', 2, 4 FROM DUAL UNION ALL
SELECT 7, 'name_c', 6, 2 FROM DUAL UNION ALL
SELECT 8, 'name_c', 2, 2 FROM DUAL;
Outputs:
ID
NAME
QUANTITY
MAXQUANTITY
TAG
EFFECTIVE_QUANTITY
1
name_a
3
5
name_a_part1
3
2
name_a
1
5
name_a_part1
1
3
name_a
3
5
name_a_part1
1
3
name_a
3
5
name_a_part2
2
4
name_a
5
5
name_a_part2
3
4
name_a
5
5
name_a_part3
2
5
name_b
7
4
name_b_part1
4
5
name_b
7
4
name_b_part2
3
6
name_b
2
4
name_b_part2
1
6
name_b
2
4
name_b_part3
1
7
name_c
6
2
name_c_part1
2
7
name_c
6
2
name_c_part2
2
7
name_c
6
2
name_c_part3
2
8
name_c
2
2
name_c_part4
2
db<>fiddle here