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Top Customers in Last 90 Days
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Top Customers in Last 90 Days

MediumSQL · PostgreSQL

Problem

Write a SQL query to find the top customers by order volume and revenue over the last 90 days.

Use the provided customers and orders tables. For deterministic evaluation, treat the 90-day period as December 31, 2024 through March 31, 2025, inclusive.

Output

  1. Return up to five customers, with one row per customer.
  2. Include customer_id, customer_name, order_volume, and total_revenue.
  3. Sort by total_revenue descending, then order_volume descending, then customer_id ascending.

Schema

customers
ColumnTypeDescription
customer_idPKINTUnique customer identifier
customer_nameVARCHAR(100)Customer display name
orders
ColumnTypeDescription
order_idPKINTUnique order identifier
customer_idINTCustomer associated with the order
order_dateDATEDate the order was placed
order_amountNUMERIC(12,2)Revenue attributed to the order
Tablescustomersorders
Interviewer

Your question is Top Customers in Last 90 Days. Start with the requirements and the two tables in the Question tab.

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