SQL Group By and NULL Handling | Dataford Interview Questions

Write a SQL query involving GROUP BY, HAVING and NULL handling.

Asked in the Round 1 stage. This was the second Anakin Round 1 question, described by the author as "SQL Query involving GROUPBY, HAVING, NULL".

Use the accounts and transactions tables.

Output

Return one row per account with at least two transactions and at least one non-NULL amount.
Include account_id, account_name, transaction_count, non_null_amount_count, and total_amount.
Replace missing account names and totals with appropriate zero or fallback values, and order by total_amount descending, then account_id ascending.

accounts

Column	Type	Description
account_idPK	INT	Unique account identifier
account_name	VARCHAR(100)	Account display name

transactions

Column	Type	Description
transaction_idPK	INT	Unique transaction identifier
account_id	INT	Account associated with the transaction
amount	DECIMAL(12,2)	Transaction amount, which may be missing

Your question is SQL Group By and NULL Handling. Start with the requirements and the two tables in the Question tab.

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