422. Average Days Between Orders per Customer

Hard E-Commerce Advanced Analytics

Query Rules

The query columns and order must match the expected result schema.
NULL values should be handled appropriately where applicable.
The grader compares output values and sorting order to evaluate.

Schema Browser

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locations

3 cols

departments

3 cols

employees

6 cols

orders

6 cols

Reference Solution

Expected SQL

WITH ordered AS (SELECT customer_name, order_date, LAG(order_date) OVER (PARTITION BY customer_name ORDER BY order_date) AS prev_order_date FROM orders) SELECT customer_name, AVG(JULIANDAY(order_date) - JULIANDAY(prev_order_date)) AS avg_days_between_orders FROM ordered WHERE prev_order_date IS NOT NULL GROUP BY customer_name ORDER BY avg_days_between_orders;

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Console Output

Console Terminal

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