SQL Dataset Discrepancy Check | Dataford Interview Questions

Write a SQL query to perform a comparison between two customer transaction datasets to identify discrepancies.

Compare records by transaction_id, treating NULL values as equal when both datasets contain NULL. Return records that are missing from either dataset or have different customer, date, amount, or status values.

Output

One row per discrepancy, with the transaction ID, discrepancy type, and values from both datasets.
Include missing records and field mismatches only.
Order by transaction_id ascending.

Schema

customer_transactions_a

Column	Type	Description
transaction_idPK	INT	Unique transaction identifier
customer_id	VARCHAR(20)	Customer identifier
transaction_date	DATE	Transaction date
amount	DECIMAL(12,2)	Transaction amount
status	VARCHAR(20)	Transaction status

customer_transactions_b

Column	Type	Description
transaction_idPK	INT	Unique transaction identifier
customer_id	VARCHAR(20)	Customer identifier
transaction_date	DATE	Transaction date
amount	DECIMAL(12,2)	Transaction amount
status	VARCHAR(20)	Transaction status

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