Flatten nested JSON into a fact table

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Explode a nested order payload into one row per line item, carrying the order-level attributes down onto every row.

Input schema

solve(payloads: list[dict]) -> list[dict] each payload: { "order_id": int, "customer_id": int, "ordered_at": str, "items": [{"sku": str, "quantity": int, "unit_price": float}, ...] }

Constraints

Column order is order_id, customer_id, ordered_at, sku, quantity, unit_price, line_total
line_total is quantity * unit_price, rounded to two decimals
An order with no items contributes no rows
Input order is preserved: orders in order, and items within an order in order

Example 1one order, two line items

Input · payloads

items	order_id	ordered_at	customer_id
[{"sku":"A1","quantity":2,"unit_price":5},{"sku":"B2","quantity":1,"unit_price":12.5}]	1	2024-01-01 09:00:00	10

Output

order_id	customer_id	ordered_at	sku	quantity	unit_price	line_total
1	10	2024-01-01 09:00:00	A1	2	5	10
1	10	2024-01-01 09:00:00	B2	1	12.5	12.5

Example 2two orders keep their own attributes