Window Functions Latest and Running Total | Dataford Interview Questions

Write a SQL query using window functions to find the latest record per user and calculate a running total.

Use the user_records table. Calculate the running total of amount separately for each user, treating NULL amounts as zero. If timestamps tie, the record with the greater record_id is later.

Output

One row per user with user_id, record_id, recorded_at, amount, and running_total
Include only each user's latest record
Order by user_id ascending

Schema

user_records

Column	Type	Description
record_idPK	INT	Unique record identifier
user_id	INT	Identifier of the user associated with the record
recorded_at	TIMESTAMPTZ	Timestamp when the record was created
amount	NUMERIC(12,2)	Amount included in the user's cumulative total

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