Rolling Member Claim Totals SQL | Dataford Interview Questions

Aetna's member analytics team needs monthly claim trend metrics for members. Write a PostgreSQL query that aggregates claim amounts by member and calendar month, then calculates both cumulative claim totals and a rolling three-month average.

Requirements

Include claims from January 1, 2025 through June 30, 2025.
Aggregate each member's claims by month, treating NULL claim amounts as zero.
Calculate a running total ordered chronologically for each member.
Calculate the average monthly claim amount for the current month and the preceding two calendar months using a window frame. Return one row for each member-month with at least one claim.

Schema

members

Column	Type	Description
member_idPK	INT	Unique member identifier
member_name	VARCHAR(100)	Member's full name
plan_type	VARCHAR(30)	Aetna health plan type

claims

Column	Type	Description
claim_idPK	INT	Unique claim identifier
member_id	INT	Member associated with the claim
claim_date	DATE	Date the claim was submitted
claim_amount	NUMERIC(12,2)	Allowed claim amount

Your question is Rolling Member Claim Totals SQL. Start with the requirements and the two tables in the Question tab.

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Problem