Terminal Query Implementation | Dataford Interview Questions

Terminal query implementation: write an interactive command-line program that supports a variety of queries.

Asked in the Onsite stage. Using the supplied merchants and payments tables, write the PostgreSQL query for the terminal report.

Output

Return one row per active merchant, including merchants with no qualifying payments.
Columns: merchant_id, merchant_name, settled_payment_count, and settled_amount.
Include only payments settled from 2025-01-01 through 2025-01-31, inclusive.
Sort by settled_amount descending, then merchant_id ascending.

merchants

Column	Type	Description
merchant_idPK	INT	Unique merchant identifier
merchant_name	VARCHAR(100)	Merchant display name
is_active	BOOLEAN	Whether the merchant is active

payments

Column	Type	Description
payment_idPK	INT	Unique payment identifier
merchant_id	INT	Merchant associated with the payment
status	VARCHAR(20)	Payment processing status
amount	NUMERIC(12,2)	Payment amount
paid_at	TIMESTAMP	Payment settlement timestamp

Your question is Terminal Query Implementation. Start with the requirements and the two tables in the Question tab.

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