Count item after joining two table - sql

Question

I have two tables,
First is Product table
+-----------+------+-----+------------+
| id | pnum | year |month|date |
+-----------+------+-----+------------+
|12 | S5 | 2021 | 2 | 2021-02-21 |
|12 | S5 | 2021 | 2 | 2021-02-22 |
|12 | S5 | 2021 | 2 | 2021-02-23 |
|33 | A55| 2021 | 3 | 2021-03-01 |
|44 | B1 | 2021 | 6 | 2021-06-01 |
Second is Deal table
+-----------+------+-----+------------+
| id | pnum| year |month|date |
+-----------+------+-----+------------+
|12 | S5 | 2021 | 2 | 2021-02-28 |
|12 | S5 | 2021 | 2 | 2021-02-01 |
|33 | A55| 2021 | 3 | 2021-03-01 |
I need a result which can tell me how many product got launch
for a year_month and count of deal in first 15 days or in next 15 days
+----------- +------------+----------------+--------------------+
| num | count| year-month |deal_in_first15 |deal_after_first15 |
+----------- +------+-----+-------------------------------------
|S5 | 3 | 2021-02 | 1 | 1 |
|A55 | 1 | 2021-03 | 1 | 0 |
I was trying to do it like below
select * from Product p inner join Deal d on
p.num=d.num AND p.id=d.id AND p.month=d.month
but it is not helping me to get exact result as intended.
I have some java and python background and not expert in sql hence applying count and case statement is not working out.

Answer 1

You can try to use the condition aggregate function in subquery then do JOIN
select p.pnum ,
COUNT(*) count,
FORMAT(p.[date],'yyyy-MM') 'year-month',
deal_in_first15 ,
deal_after_first15
from Product p
inner join (
SELECT id ,
pnum ,
month,
year ,
COUNT(CASE WHEN DATEPART(day,[date]) < 15 THEN 1 END) deal_in_first15 ,
COUNT(CASE WHEN DATEPART(day,[date]) >= 15 THEN 1 END) deal_after_first15
FROM Deal
GROUP BY id ,pnum ,month,year
) d on
p.pnum=d.pnum AND p.id=d.id AND p.month=d.month
group by FORMAT(p.[date],'yyyy-MM') ,
p.pnum,
deal_in_first15 ,
deal_after_first15
I think there is another way might you want, using two subquery then JOIN
select p.pnum ,
p.cnt 'count',
CONCAT(p.year,'-',FORMAT(p.month,'0#')) 'year-month',
deal_in_first15 ,
deal_after_first15
from (
SELECT id ,
pnum ,
month,
year,
count(*) cnt
FROM Product
GROUP BY id ,
pnum ,
month,
year
) p
inner join (
SELECT id ,
pnum ,
month,
year ,
COUNT(CASE WHEN DATEPART(day,[date]) < 15 THEN 1 END) deal_in_first15 ,
COUNT(CASE WHEN DATEPART(day,[date]) >= 15 THEN 1 END) deal_after_first15
FROM Deal
GROUP BY id ,pnum ,month,year
) d on
p.pnum=d.pnum
AND p.id=d.id
AND p.month=d.month
AND p.year=d.year
sqlfiddle
Note
I would use the year column to be JOIN condition. otherwise, the result will be wrong when you cross-year meet the same month.

Answer 2

This is it:
select pnum,cnt,sum(mn1),sum(mn2) from (select d."pnum",(select count(*) from Product p where p."pnum"=d."pnum"
) cnt,
case when
EXTRACT(DAY FROM d."date")<=15 then sum(1) else sum(0) end mn1 ,
case when
EXTRACT(DAY FROM d."date")>15 then sum(1) else sum(0) end mn2,
d."year"||'-'||d."month"
from deal d
group by 1,d."year"||'-'||d."month",d."date")abc group by 1,2;
please check at:http://sqlfiddle.com/#!17/3bad9/18