Exclude certain values when splitting a fix value to countries based on a daily revenue share

问题

DB-Fiddle

CREATE TABLE sales (
    id int auto_increment primary key,
    country VARCHAR(255),
    sales_date DATE,
    sales_volume INT,
    fix_costs INT
);

INSERT INTO sales
(country, sales_date, sales_volume, fix_costs
)
VALUES 

("DE", "2020-01-03", "500", "0"),
("NL", "2020-01-03", "320", "0"),
("FR", "2020-01-03", "350", "0"),
("None", "2020-01-30", "0", "2000"),

("DE", "2020-02-15", "700", "0"),
("NL", "2020-02-15", "420", "0"),
("FR", "2020-02-15", "180", "0"),
("None", "2020-02-29", "0", "5000"),

("DE", "2020-03-27", "180", "0"),
("NL", "2020-03-27", "670", "0"),
("FR", "2020-03-27", "970", "0"),
("None", "2020-03-31", "0", "4000");

Expected Result:

sales_date      country       sales_volume     fix_costs
2020-01-03        DE              500           37.95  (=2000/31 = 64.5 * 0.59)
2020-01-03        FR              350           26.57  (=2000/31 = 64.5 * 0.41)
2020-01-03        NL              320            0.00
2020-02-15        DE              700          137.15  (=5000/29 = 172.4 * 0.8)   
2020-02-15        FR              180           35.27  (=5000/29 = 172.4 * 0.2)  
2020-02-15        NL              420            0.00    
2020-03-27        DE              180           20.20  (=4000/31 = 129.0 * 0.16) 
2020-03-27        FR              970          108.81  (=4000/31 = 129.0 * 0.84)   
2020-03-27        NL              670            0.00

---

With reference to the solution in this question I currently use the below query to divide the monthly fix_costs on a daily basis to each country:

select 
    sales_date, 
    country, 
    sum(sales_volume),
    sum(sum(fix_costs)) over(partition by year(sales_date), month(sales_date))
        / day(last_day(sales_date)) 
        * sum(sales_volume)
        / sum(sum(sales_volume)) over(partition by sales_date)
        as fix_cost_per_day
from sales
group by 1,2;

All this works fine.

---

However, now I want that country NL is excluded from the share_calculation and always remains 0 as you can see in the expected results. How do I have to modify the query to achieve this?

回答1:

You can use case expressions, both around the computation and within the window sum:

select 
    sales_date, 
    country, 
    sum(sales_volume),
    case when country <> 'NL'
        then sum(sum(fix_costs)) over(partition by year(sales_date), month(sales_date))
            / day(last_day(sales_date)) 
            * sum(sales_volume)
            / sum(case when country <> 'NL' then sum(sales_volume) else 0 end) over(partition by sales_date)
    else 0
    end as fix_cost_per_day
from sales
group by 1,2;

Demo on DB Fiddle:

sales_date | country | sum(sales_volume) | fix_cost_per_day
:--------- | :------ | ----------------: | ---------------:
2020-01-03 | DE      |               500 |      37.95066414
2020-01-03 | FR      |               350 |      26.56546490
2020-01-03 | NL      |               320 |             null
2020-01-30 | None    |                 0 |             null
2020-02-15 | DE      |               700 |     137.14733542
2020-02-15 | FR      |               180 |      35.26645768
2020-02-15 | NL      |               420 |             null
2020-02-29 | None    |                 0 |             null
2020-03-27 | DE      |               180 |      20.19635344
2020-03-27 | FR      |               970 |     108.83590463
2020-03-27 | NL      |               670 |             null
2020-03-31 | None    |                 0 |             null

回答2:

Just use conditional aggregation:

select 
    sales_date, 
    country, 
    sum(sales_volume),
    (case when country = 'NL' then 0
          else sum(sum(case when country = 'NL' then 0 else fix_costs end)) over(partition by year(sales_date), month(sales_date)) / day(last_day(sales_date)) *
               sum(sales_volume) /
               sum(sum(sales_volume)) over(partition by sales_date)
     end)  as fix_cost_per_day
from sales
group by 1,2;

来源：https://stackoverflow.com/questions/62997226/exclude-certain-values-when-splitting-a-fix-value-to-countries-based-on-a-daily