Find Duplicate Transaction Records | Dataford Interview Questions

Write a SQL query to identify duplicate records in a transaction table at i2c.

Treat records as duplicates when all business columns match, excluding transaction_id. Include duplicate records even when matching columns contain NULL values.

Output

One row per duplicate transaction, including transaction_id, all business columns, and duplicate_count.
Exclude transaction groups that occur only once.
Order by transaction_id ascending.

Schema

transactions

Column	Type	Description
transaction_idPK	INT	Unique transaction record identifier
card_token	VARCHAR(32)	Tokenized card identifier
merchant_id	INT	Merchant identifier
amount	NUMERIC(12,2)	Transaction amount
currency	VARCHAR(3)	ISO currency code
transaction_time	TIMESTAMP	Time the transaction was recorded
transaction_type	VARCHAR(20)	Transaction operation type
status	VARCHAR(20)	Processing status

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