Calculate all days, group by week and include empty weeks? - sql

Question

I need a query that sums all the values for each day in a given week and groups by week including empty weeks.
This query groups by week and includes empty weeks but it isn't summing all days in the week as expected:
Expected Output:
[
...
{"week"=>"2019-02-28", "amount_net"=>"0"},
{"week"=>"2019-03-07", "amount_net"=>"300"}
]
Actual Output:
[
...
{"week"=>"2019-02-28", "amount_net"=>"0"},
{"week"=>"2019-03-07", "amount_net"=>"0"}
]
Here is the query I came up with:
SELECT
week,
COALESCE (amount_net, 0) as amount_net
FROM
(
SELECT
to_char(
generate_series(
timestamp '2018-12-13 22:34:31 UTC',
timestamp '2019-03-14', interval '1 week'
):: date,
'YYYY-MM-DD'
) as week
) d
LEFT JOIN (
SELECT
to_char(
date_trunc('week', created_at),
'YYYY-MM-DD'
) AS week,
SUM(
ROUND(
(
coalesce(cost_items.base_price, 0) - coalesce(cost_items.base_discount, 0) + coalesce(cost_items.base_fee, 0) + coalesce(cost_items.base_taxes_total, 0) + coalesce(
cost_items.base_commission_included,
0
) - coalesce(cost_items.base_voided_price, 0) + coalesce(
cost_items.base_voided_discount,
0
) - coalesce(cost_items.base_voided_fee, 0) - coalesce(
cost_items.base_voided_taxes_total,
0
) - coalesce(
cost_items.base_voided_commission_included,
0
)
):: numeric,
2
)
) as amount_net
FROM
cost_items
WHERE
id IN ('0', '1', '2')
GROUP BY
1
) t USING (week)
ORDER BY
week;
How do I adjust this query to properly sum all values for each day in the week?

Answer 1

Figured it out:
with host_weeks as (
SELECT
generate_series(
timestamp '2018-12-01',
timestamp '2019-04-01', interval '1 day'
)::date as host_week )
select date_trunc('week', day)::date as week, sum(amount_net) from
(
select hw.host_week as day,
SUM(
ROUND(
(
coalesce(ci.base_price, 0) - coalesce(ci.base_discount, 0) + coalesce(ci.base_fee, 0) + coalesce(ci.base_taxes_total, 0) + coalesce(
ci.base_commission_included,
0
) - coalesce(ci.base_voided_price, 0) + coalesce(
ci.base_voided_discount,
0
) - coalesce(ci.base_voided_fee, 0) - coalesce(
ci.base_voided_taxes_total,
0
) - coalesce(
ci.base_voided_commission_included,
0
)
):: numeric,
2
)
) as amount_net
from host_weeks hw left join cost_items ci on hw.host_week = ci.created_at::date and ci.id in (....)
group by 1 order by 1) t group by 1 order by 1;