Yes, there's a way to create the Sales by Customer report that compares your twelve months' worth of sales in QuickBooks Online (QBO), @juma1. I'm here to guide you how.
You can compare two months of your sales when pulling up the Sales by Customer (Summary) report through the Compare another period feature. Then, to acquire such a report that provides your twelve months' worth of sales, you'll have to manually update the Report period and Display columns by fields. Here's how:
- Go to the Reports menu.
- Type in Sales in the search box, then select Sales by Customer Summary.
- In the Report period field, select the Custom option. Then type in the dates in the From and To fields.
- Choose Months in the Display columns by field.
- Select Run report.
I've attached screenshots below for your reference.


After customizing the sales report, you can memorize it to save its current customization setting. For the detailed steps, kindly check out this article: Memorize reports in QuickBooks Online. It also contains information in scheduling and emailing a memorized report and add it to a group.
I'm also adding this article for the complete list of reports available for your QBO version: Reports included in your QuickBooks Online subscription. It includes sections like business overview, sales and customer, and who owes you to name a few.
Please let me know if you have other concerns. I'm just around to help. Take care always.