Only this week, get the SQL Complete Track of 9 courses in a special prize of $330$89!
Introduction
GROUPING SETS
Summary

## Instruction

Well done! Let's say we also need to add the general average repair duration to our report. To that end, we can use an empty pair of parentheses:

SELECT
CustomerId,
RepairCenter,
AVG(RepairDuration) AS AvgRepairDuration
FROM WarrantyRepair
GROUP BY GROUPING SETS
(
(CustomerId, RepairCenter),