Build KPIs With SQL and Python | Dataford Interview Questions

How would you use Python string manipulation and basic data structures, along with SQL, to build KPIs from a sample dataset?

Use the provided sample dataset to produce a KPI summary by customer plan. Treat status values case-insensitively after trimming whitespace, and count revenue only for completed orders.

Output

One row per customer plan with plan, customer_count, total_orders, completed_orders, completion_rate_pct, completed_revenue, and avg_completed_order_value.
Include plans with no orders, use zero for unavailable KPI values, and order by completed_revenue descending, then plan ascending.

Schema

customers

Column	Type	Description
customer_idPK	INT	Unique customer identifier
customer_name	VARCHAR(100)	Customer display name
plan	VARCHAR(30)	Customer plan
signup_date	DATE	Date the customer signed up

orders

Column	Type	Description
order_idPK	INT	Unique order identifier
customer_id	INT	Customer associated with the order
order_date	DATE	Date the order was created
status	VARCHAR(30)	Order status, potentially inconsistently formatted
amount	NUMERIC(10,2)	Order amount

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Problem