Top N Per Group Query | Dataford Interview Questions

CustomerInsights.AI needs one highest-performing insight record from each dashboard group. Write a PostgreSQL query that returns the top record per group_name, where performance is measured by metric_value.

Requirements

Return exactly one record for each group_name.
Select the record with the greatest non-NULL metric_value; use the smallest record_id to break ties.
Return the group, record name, and metric value, ordered by group name.

Schema

insight_records

Column	Type	Description
record_idPK	INT	Unique insight record identifier
group_name	VARCHAR(100)	CustomerInsights.AI insight group
record_name	VARCHAR(150)	Name of the insight record
metric_value	DECIMAL(10,2)	Performance metric used for ranking

Your question is Top N Per Group Query. Start with the requirements and the one table in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.

Problem

Requirements

Return exactly one record for each group_name.
Select the record with the greatest non-NULL metric_value; use the smallest record_id to break ties.
Return the group, record name, and metric value, ordered by group name.

Schema

insight_records

Column	Type	Description
record_idPK	INT	Unique insight record identifier
group_name	VARCHAR(100)	CustomerInsights.AI insight group
record_name	VARCHAR(150)	Name of the insight record
metric_value	DECIMAL(10,2)	Performance metric used for ranking

Your question is Top N Per Group Query. Start with the requirements and the one table in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.