List campaigns: Calculate number of orders for a promotion

Description

The Campaign view now displays numbers for each campaign and discount.
For each campaign, you see the number of orders that include discounts. If an order has multiple discounts that belong to different campaigns, that order increases each campaign's total.

For each discount, the Campaign view displays

• the total number of orders that include it.
• redemptions, the number of times a discount reduces cost.

This information enables the marketer to get feedback on how a promotion/Campaign is performing.