For each ad campaign, show the total impression count and a list of all unique viewers

A medium SQL interview practice problem on DataDriven. Write and execute real sql code with instant grading.

Domain

SQL

Difficulty

medium

Problem

For each ad campaign, show the total impression count and a list of all unique viewers. Return ad_campaign, impression_count, and viewers.

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Solve this SQL problem with real code execution. DataDriven runs your SQL queries against a real database and grades it automatically.