Top Incident Growth Customers | Dataford Interview Questions

Write a SQL query to find the top 5 customers with the highest increase in incidents over the last 30 days.

Compare each customer's incident count in the last 30 days with the immediately preceding 30-day period. Include customers with no incidents in either period.

Output

One row per selected customer with customer_id, customer_name, previous_30_day_incidents, last_30_day_incidents, and incident_increase
Return the five largest increases, ordered by incident_increase descending, then customer_name ascending, then customer_id ascending

Schema

customers

Column	Type	Description
customer_idPK	INT	Unique customer identifier
customer_name	VARCHAR(150)	Customer display name
account_status	VARCHAR(20)	Current customer account status

incidents

Column	Type	Description
incident_idPK	INT	Unique incident identifier
customer_id	INT	Customer associated with the incident
created_at	TIMESTAMP	Incident creation timestamp
severity	VARCHAR(20)	Incident severity classification
resolved	BOOLEAN	Whether the incident has been resolved

Your question is Top Incident Growth Customers. Start with the requirements and the two tables in the Question tab.

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Problem