SQL Oracle - Sales Forecast - sql

Question

I am doing a Seles forecast in SQL Oracle. I need to figure out what revenue I can expect for next year. I should calculate for each month(In my example January, February 2018 for Each customer by State/City) . I have data for 3 years.
The result should contain an estimated sales forecast for each month based on the city+state combination. I was trying to use use req_slope, but it doesn't work. I have code here: SQL Fiddle
select c.*,
max(year) +1 forecast_year,
regr_slope(revenue, year)
* (max(year) + 1)
+ regr_intercept(revenue, year) forecasted_revenue
from New_customer_data c
group by Cust_ID ,
State ,
City ,
year ,
id_month ,
revenue ;

Answer 1

I need to figure out what revenue I can expect for next year.
Remove revenue and year from the GROUP BY clause as those are the columns you want to perform the regression on:
select cust_id,
city,
state,
id_month,
max(year) +1 forecast_year,
regr_slope(revenue, year)
* (max(year) + 1)
+ regr_intercept(revenue, year) forecasted_revenue
from New_customer_data c
group by
Cust_ID,
city,
state,
id_month;
Which, for your sample data:
insert into New_customer_data
select 1, 'MN' , 'Minneapolis', 2016, 1, 679862 from dual union all
select 1, 'IL', 'Chicago' , 2016, 2, 11862 from dual union all
select 1, 'MN' , 'Minneapolis', 2017, 1,547365 from dual union all
select 1, 'IL', 'Chicago' , 2017, 2, 705365 from dual union all
select 2, 'CA', 'San Diego', 2016, 1, 51074 from dual union all
select 2, 'CA', 'LA', 2016, 2, 598862 from dual union all
select 2, 'CA', 'San Diego', 2017, 1, 705365 from dual union all
select 2,'CA', 'LA', 2017, 2, 50611 from dual union all
select 3, 'CA', 'Santa Monica', 2016, 1, 190706 from dual union all
select 3, 'IL', 'Evanston', 2016, 2, 679862 from dual union all
select 3, 'CA', 'Santa Monica', 2017, 1, 705365 from dual union all
select 3, 'IL', 'Evanston', 2017, 2, 90393 from dual union all
select 4, 'MN', 'Shakopee', 2016, 1, 31649 from dual union all
select 4, 'FL', 'Miami', 2016, 2,888862 from dual union all
select 4, 'MN', 'Shakopee', 2017, 1, 125365 from dual union all
select 4, 'FL', 'Miami', 2017, 2, 30566 from dual;
Outputs:
CUST_ID
CITY
STATE
ID_MONTH
FORECAST_YEAR
FORECASTED_REVENUE
1
Minneapolis
MN
1
2018
414868
1
Chicago
IL
2
2018
1398868
2
San Diego
CA
1
2018
1359656
2
LA
CA
2
2018
-497640
3
Santa Monica
CA
1
2018
1220024
3
Evanston
IL
2
2018
-499076
4
Shakopee
MN
1
2018
219081
4
Miami
FL
2
2018
-827730
db<>fiddle here