How the Window Changes the Output

SELECT vendor_id, invoice_date, invoice_total,

SUM(invoice_total) OVER() AS total_invoices,

SUM(invoice_total) OVER(PARTITION BY vendor_id)

AS vendor_total

FROM invoices

WHERE invoice_total > 5000

Here we have 2 Windows, one with no Partition and one with a Partition by vendor_id

Notice that the total_invoices column totals all invoices because the Partition was everything

Notice that the vendor_total column totals based on the Partition field : vendor_id