Clean Null Campaign Metrics | Dataford Interview Questions

You are given a single table of daily StackAdapt campaign performance metrics. Some rows have missing values in impressions, clicks, or spend. Write a SQL query that returns each campaign_name with the number of rows that contain at least one null metric and the average spend after treating null spend values as 0.

This tests whether you can handle incomplete performance data safely in PostgreSQL without dropping rows that still matter for reporting.

Schema

campaign_metrics

Column	Type	Description
idPK	INT	Unique row identifier
campaign_name	VARCHAR(100)	StackAdapt campaign name
metric_date	DATE	Date of the performance record
impressions	INT	Number of impressions served
clicks	INT	Number of clicks recorded
spend	DECIMAL(10,2)	Daily spend in dollars

Your question is Clean Null Campaign Metrics. 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

This tests whether you can handle incomplete performance data safely in PostgreSQL without dropping rows that still matter for reporting.

Schema

campaign_metrics

Column	Type	Description
idPK	INT	Unique row identifier
campaign_name	VARCHAR(100)	StackAdapt campaign name
metric_date	DATE	Date of the performance record
impressions	INT	Number of impressions served
clicks	INT	Number of clicks recorded
spend	DECIMAL(10,2)	Daily spend in dollars

Your question is Clean Null Campaign Metrics. 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.