1-test.sql

with _data as (
  select
    date_trunc('week', orders.completed_at) as week, --tried to change to EST with convert_timezone('EST', completed_at) but didn't work
    sum(orders.order_total)  as sales_total,
    users.signup_channel as signup_channel,
    orders.order_category as order_category,
    concat(concat(signup_channel, ' - '), order_category) as series --didn't understand how to use as a series
  from orders
  join users
  on users.user_id = orders.user_id
  where completed_at between '2019-10-01' and '2019-12-31'
  group by week, signup_channel, order_category, series
)
select
  week,
  signup_channel,
  order_category,
  sum(sales_total) over (order by week asc rows unbounded preceding) as Total_Running_Sales
from _data;