Cannot generate a sales by customer report?

We can customize the Sales by Customer Detail report in QuickBooks Online.

You can run the Sales by Customer Detail report and customize it by following these steps:

1. On the left panel, click Reports.
2. Type Sales by Customer Detail in the search box.
3. Choose the Report period, and click the Customize button.
4. Click Filter to expand, and choose the customer you want to view from the Customer drop-down list.
5. Select All from the Product/Service drop-down menu.
6. Click Run Report.

You can also check this article for reference: How to Customize Reports.

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