Select 9 Columns, Subtotal Only Based on First Column

[Darren McGettigan]

Here is my query so far:

SELECT CustomerNumber, CustomerName, City, InvoiceNumber, MFG, PartNumber, PartDescription, Quantity, SUM(TotalSale) as 'Total'
FROM wp_sales_data
WHERE Date >= '2018-06-25'
AND Date <= '2018-06-30'
AND PriceLevel = '138'
GROUP BY CustomerNumber, CustomerName, City, InvoiceNumber, MFG, PartNumber, PartDescription, Quantity, TotalSale WITH ROLLUP

When using ROLLUP, it gives me a 'subtotal' for each and every column.

How do I go about getting just a 'subtotal' for 'CustomerNumber'