Multiple joins on same table giving duplicate data - sql

Question

Here is the sale_order table which contains CCNID
sale_orderid client_channel_nameid
1 1
2 1
3 2
4 2
5 2
6 2
7 1
8 1
sale_order_item Table has sale_orderid as a foreign key
sale_order_itemid sale_orderid order_date selling_price
42219 1 2018-03-21 00:00:00 200
28948 2 2018-03-21 16:17:55 100
42220 3 2018-03-21 00:00:00 300
13194 4 2018-03-21 13:33:58 400
42839 5 2018-03-20 07:54:29 550
42840 6 2018-03-20 07:58:20 600
42086 7 2018-03-20 00:00:00 700
11691 8 2018-03-20 05:32:31 500
And I want to get the sum of price of soid of 21 and 20 dates in different columns grouped by CCNID
client_channel_nameid 21 20
1 300 1200
2 700 1150
I am joining Sale order twice which is giving me wrong results
select ccn.client_channel_nameid,
round (sum(soi.selling_price)),
round(sum(soi1.selling_price))
from app.client_channel_name ccn
join app.sale_order so on so.client_channel_nameid = ccn.client_channel_nameid
inner join app.sale_order_item soi on soi.sale_orderid = so.sale_orderid
join app.sale_order so1 on so1.client_channel_nameid = ccn.client_channel_nameid
inner join app.sale_order_item soi1 on soi1.sale_orderid = so1.sale_orderid
where ccn.clientid = 1
and to_char(soi.order_date, 'DD-MM-YYYY') = '20-03-2018'
and to_char(soi1.order_date, 'DD-MM-YYYY') = '21-03-2018'
group by client_channel_nameid;

Answer 1

You can group the data by CCNID and then only sum selling_price when the order_date day is the 21 or 20.
SELECT client_channel_nameid
, SUM(CASE
WHEN EXTRACT(day FROM order_date) = 21 THEN selling_price
ELSE 0
END) AS "21"
, SUM(CASE
WHEN EXTRACT(day FROM order_date) = 20 THEN selling_price
ELSE 0
END) AS "20"
FROM sale_order so
JOIN sale_order_item soi
ON soi.sale_orderid = so.sale_orderid
GROUP BY so.client_channel_nameid

Answer 2

Below query produce the desired result. From your above tried solution and question you asked I think you are looking for exactly 21 and 20 dates. The below will need slight changes with extra filters for add more dates ex.22,23,24...
with sale_order(
sale_orderid, client_channel_nameid
) as (
select
*
from
(
values
(1, 1),
(2, 1),
(3, 2),
(4, 2),
(5, 2),
(6, 2),
(7, 1),
(8, 1)
) as x(
sale_orderid, client_channel_nameid
)
),
sale_order_item(
sale_order_itemid, sale_orderid,
order_date, selling_price
) as (
select
*
from
(
values
(
42219, 1, '2018-03-21 00:00:00' :: timestamp,
200
),
(
28948, 2, '2018-03-21 16:17:55' :: timestamp,
100
),
(
42220, 3, '2018-03-21 00:00:00' :: timestamp,
300
),
(
13194, 4, '2018-03-21 13:33:58' :: timestamp,
400
),
(
42839, 5, '2018-03-20 07:54:29' :: timestamp,
550
),
(
42840, 6, '2018-03-20 07:58:20' :: timestamp,
600
),
(
42086, 7, '2018-03-20 00:00:00' :: timestamp,
700
),
(
11691, 8, '2018-03-20 05:32:31' :: timestamp,
500
)
) as x(
sale_order_itemid, sale_orderid,
order_date, selling_price
)
)
select
client_channel_nameid,
sum(selling_price) filter (where to_char(order_date, 'dd-mm-yy') = '21-03-2018') as date_21,
sum(selling_price) filter (where to_char(order_date, 'dd-mm-yy') = '20-03-2018') as date_20
from
sale_order so
join sale_order_item soi on soi.sale_orderid = so.sale_orderid
group by
so.client_channel_nameid