from i=invoices
join ii=invoice_items [==invoice_id]
derive [
    month = s"STRFTIME('%Y-%m', {i.invoice_date})",
    day = s"STRFTIME('%Y-%m-%d', {i.invoice_date})",
]
group [month, day] (
    aggregate [
        num_orders = s"COUNT(DISTINCT {i.invoice_id})",
        num_tracks = sum ii.quantity,
        total_price = sum (ii.unit_price * ii.quantity),
    ]
)
group [month] (
    sort day
    window expanding:true (
        derive [running_total_num_tracks = sum num_tracks]
    )
)
sort day
derive [num_tracks_last_week = lag 7 num_tracks]