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SQL Average for On-Time Customers
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SQL Average for On-Time Customers

MediumSQL · PostgreSQL

Problem

American Credit Acceptance wants to identify the average original loan principal for customers whose payment records show no missed payments during the most recent six-month review period. Assume the reporting date is July 1, 2024, so the review period runs from January 1 through June 30, 2024.

Write a PostgreSQL query that returns the average loan amount for loans belonging to qualifying customers.

Requirements

  1. Evaluate only payment due dates from January 1 through June 30, 2024.
  2. Treat a customer as qualified only when they have at least one payment in the period and every reviewed payment has a payment_status of PAID.
  3. Exclude customers with MISSED, LATE, or NULL payment statuses.
  4. Return one value named average_loan_amount, rounded to two decimal places.

Schema

customers
ColumnTypeDescription
customer_idPKINTUnique American Credit Acceptance customer identifier
customer_nameVARCHAR(100)Customer full name
loans
ColumnTypeDescription
loan_idPKINTUnique loan identifier
customer_idINTCustomer who owns the loan
loan_amountNUMERIC(12,2)Original loan principal
loan_typeVARCHAR(50)Loan product classification
payments
ColumnTypeDescription
payment_idPKINTUnique payment record identifier
loan_idINTLoan associated with the payment
due_dateDATEScheduled payment due date
payment_statusVARCHAR(20)Payment status, such as PAID, LATE, or MISSED
Tablescustomersloanspayments
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