Detect Missed Consecutive Installments | Dataford Interview Questions

Given a table of customer repayments, write a query to identify users who have missed consecutive monthly installments for Navi's lending portfolio. Treat repayment records as monthly installments and return every streak containing at least two consecutive missed months.

Output

One row per qualifying user streak, with user_id, missed_start_month, missed_end_month, and missed_months
Exclude isolated missed months and incomplete records without a user or installment month
Order by user_id, then missed_start_month ascending

Schema

customer_repayments

Column	Type	Description
repayment_idPK	INT	Unique repayment record identifier
user_id	VARCHAR(20)	Navi lending customer identifier
installment_month	DATE	Scheduled installment date
repayment_status	VARCHAR(20)	Repayment outcome, such as PAID or MISSED
amount_due	NUMERIC(12,2)	Scheduled installment amount

Your question is Detect Missed Consecutive Installments. Start with the requirements and the one table in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.

Problem

Output

One row per qualifying user streak, with user_id, missed_start_month, missed_end_month, and missed_months
Exclude isolated missed months and incomplete records without a user or installment month
Order by user_id, then missed_start_month ascending

Schema

customer_repayments

Column	Type	Description
repayment_idPK	INT	Unique repayment record identifier
user_id	VARCHAR(20)	Navi lending customer identifier
installment_month	DATE	Scheduled installment date
repayment_status	VARCHAR(20)	Repayment outcome, such as PAID or MISSED
amount_due	NUMERIC(12,2)	Scheduled installment amount

Your question is Detect Missed Consecutive Installments. Start with the requirements and the one table in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.