Finding categories that make up 70% of total turnover in SQL-CodePudding

I want to find the categories that make up a certain percentage of sales, and segment them according to their percentages in SQL. To do this, I must first sort them by their revenues in descending order and then select the top N percent. For example, if the total revenue is 20M:

Category Revenue
1        6.000.000
2        4.000.000
3        4.000.000
4        3.000.000
5        1.500.000
6        500.000
7        400.000
8        300.000
9        200.000
10       100.000
        
Total    20.000.000

-Categories that make up 70% (14M) of revenue - segment A

-Categories that make up 15% (3M) - segment B

-Categories that make up 10% (2M) - segment C

-Categories that make up 5% (1M) - segment D

So, the segments should be like this:

Category Segment
1        A
2        A
3        A
4        B
5        C
6        C
7        D
8        D
9        D
10       D

CodePudding user response：

I'm sure there's a simpler way of getting this result, but here's one [rather long] query that classifies the categories in segments according to your logic:

with 
q as (
  select *,
    sum(revenue) over(order by revenue desc) as acc_revenue,
    sum(revenue) over() as tot_revenue
  from t
),
a as (
  select * from q where acc_revenue <= 0.7 * tot_revenue
),
b as (
  select * 
  from q
  where acc_revenue - (select max(acc_revenue) from a) <= 0.15 * tot_revenue
    and category not in (select category from a)
),
c as (
  select *
  from q
  where acc_revenue - (select max(acc_revenue) from b) <= 0.10 * tot_revenue
    and category not in (select category from a)
    and category not in (select category from b)
),
d as (
  select *
  from q
  where category not in (select category from a)
    and category not in (select category from b)
    and category not in (select category from c)
)
select *, 'A' as segment from a
union all select *, 'B' from b
union all select *, 'C' from c
union all select *, 'D' from d

Result:

 category  revenue  acc_revenue  tot_revenue  segment 
 --------- -------- ------------ ------------ ------- 
 1         6000000  6000000      20000000     A       
 2         4000000  14000000     20000000     A       
 3         4000000  14000000     20000000     A       
 4         3000000  17000000     20000000     B       
 5         1500000  18500000     20000000     C       
 6         500000   19000000     20000000     C       
 7         400000   19400000     20000000     D       
 8         300000   19700000     20000000     D       
 9         200000   19900000     20000000     D       
 10        100000   20000000     20000000     D

See running example at DB Fiddle.