Write a query using SQL window functions to calculate a running 30-day moving average of user activity per system.
Use activity_logs to calculate daily activity as the total of activity_units. Treat NULL activity units as zero. The 30-day period includes the current activity date and the preceding 29 calendar days.
system_name, activity_date, daily_activity, and moving_30_day_avg.system_name, then activity_date ascending.| Column | Type | Description |
|---|---|---|
| system_idPK | INT | Unique system identifier |
| system_name | VARCHAR(100) | System display name |
| classification | VARCHAR(30) | System classification |
| Column | Type | Description |
|---|---|---|
| activity_idPK | INT | Unique activity record identifier |
| user_id | INT | Identifier of the user generating activity |
| system_id | INT | System associated with the activity |
| activity_date | DATE | Calendar date of the activity |
| activity_units | INT | Number of activity units recorded |