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Payments by Type With Unique Customers

MediumSQL · PostgreSQL00:00
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Your question is Payments by Type With Unique Customers. Start with the requirements and the two tables on the right.

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Problem

Calculate the total value of sales and the number of unique paying customers, grouped and sorted in descending order by payment type.

Use the sales and customers tables, including only valid paid sales associated with a customer.

Output

  1. One row per payment type, including NULL payment types
  2. Columns: payment_type, total_sales_value, and unique_paying_customers
  3. Sort by total_sales_value descending, with NULL payment types last and payment type ascending as the tie-breaker

Schema

sales
ColumnTypeDescription
sale_idPKINTUnique sale identifier
customer_idINTCustomer associated with the sale
payment_typeVARCHAR(30)Payment method used for the sale
sale_valueNUMERIC(12,2)Value of the sale
sale_statusVARCHAR(20)Sale processing status
customers
ColumnTypeDescription
customer_idPKINTUnique customer identifier
customer_nameVARCHAR(100)Customer display name
customer_regionVARCHAR(40)Customer service region
Tablessalescustomers
Your solutionPostgreSQL
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