Split a row into multiple rows - Teradata - teradata

Question

Below is an example of my table
Names Start_Date Orders Items
AAA 2020-01-01 300 100
BAA 2020-02-01 896 448
My requirement would be as below
Names Start_Date Orders
AAA 2020-01-01 100
AAA 2020-01-01 100
AAA 2020-01-01 100
BBB 2020-02-01 448
BBB 2020-02-01 448
The rows should be split based on the (Orders/Items) value

Answer 1

This is a nice task for Teradata's SQL extension to create time series (based on #Andrew's test data):
SELECT *
FROM vt_foo
EXPAND ON PERIOD(start_date, start_date + Cast(Ceiling(Cast(orders AS FLOAT)/items) AS INT)) AS pd
For an exact split of orders into items:
SELECT dt.*,
CASE WHEN items * (end_date - start_date) > orders
THEN orders MOD items
ELSE items
end
FROM
(
SELECT t.*, End(pd) AS end_date
FROM vt_foo AS t
EXPAND ON PERIOD(start_date, start_date + Cast(Ceiling(Cast(orders AS FLOAT)/items) AS INT)) AS pd
) AS dt

Answer 2

This calls for a recursive CTE. Here's how I'd approach it, with a lovely volatile table for some sample data.
create volatile table vt_foo
(names varchar(100), start_date date, orders int, items int)
on commit preserve rows;
insert into vt_foo values ('AAA','2020-01-01',300,100);
insert into vt_foo values ('BAA','2020-02-01',896,448);
insert into vt_foo values ('CCC','2020-03-01',525,100); -
with recursive cte (names, start_date,items, num, counter) as (
select
names,
start_date,
items,
round(orders /( items * 1.0) ) as num ,
1 as counter
from vt_foo
UNION ALL
select
a.names,
a.start_date,
a.items,
b.num,
b.counter + 1
from vt_foo a
inner join cte b
on a.names = b.names
and a.start_date =b.start_date
where b.counter + 1 <= b.num
)
select * from cte
order by names,start_date
This bit: b.counter + 1 <= b.num is the key to limiting the output to the proper # of rows per product/date.
I think this should be ok, but test it with small volumes of data.