Finding Duplicates with Window Functions | Dataford Interview Questions

Write a query utilizing window functions such as ROW_NUMBER or DENSE_RANK to identify duplicate records in a dataset.

Treat records as duplicates when all columns except record_id have identical values. Return every record belonging to a duplicate group, including its occurrence number and total duplicate count.

Output

One row per record in a duplicate group.
Return record_id, duplicate-defining columns, duplicate_sequence, and duplicate_count.
Sort by the duplicate-defining columns, then record_id ascending.

Schema

dataset_records

Column	Type	Description
record_idPK	INT	Unique record identifier
customer_email	VARCHAR(255)	Customer email associated with the record
event_type	VARCHAR(50)	Type of recorded event
event_date	DATE	Date when the event occurred
amount	DECIMAL(10,2)	Amount associated with the event

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