Rolling 7-Day Unique Viewership

Write an advanced SQL query to calculate the rolling 7-day unique viewership for a specific advertising campaign across multiple regions.

Use campaign 1 and include every assigned region for each report date from the campaign's first recorded view through its last recorded view. A viewer counts once per region within each seven-day period, and dates with no views must still appear.

Output

1. One row per region and report date, including regions with zero viewers
2. Columns: region_name, report_date, rolling_unique_viewers
3. Sort by region_name, then report_date ascending