How to assign equal revenue weight to every location of a company in a table? Google Big Query - sql

Question

I am working on a problem where I have the following table:
+----------+ | +------+ | +------------+
company_id | country | total revenue
1 Russia 1200
2 Croatia 1200
2 Italy 1200
3 USA 1200
3 UK 1200
3 Italy 1200
There are 3 companies in this table, but company '2' and company '3' have offices in 2 and 3 countries respectively. All companies pay 1200 per month, and because company 2 has 2 offices it shows as if they paid 1200 per month 2 times, and because company 3 has 3 offices it shows as if it paid 1200 per month 3 times. Instead, I would like revenue to be equally distributed based on how many times company_id appears in the table. company_id will only appear more than once for every additional country in which a company is based.
Assuming each company always pays 1,200 per month, my desired output is:
+----------+ | +------+ | +------------+
company_id | country | total revenue
1 Russia 1200
2 Croatia 600
2 Italy 600
3 USA 400
3 UK 400
3 Italy 400
Being new to SQL, I was thinking this can maybe be done through CASE WHEN statement, but I only learned to use CASE WHEN when I want to output a string depending on a condition. Here, I am trying to assign equal revenue weight to each company's country, depending on in how many countries a company is based in.
Thank you in advance for you help!

Answer 1

Below is for BigQuery Standard SQL
#standardSQL
SELECT company_id, country,
total_revenue / (COUNT(1) OVER(PARTITION BY company_id)) AS total_revenue
FROM `project.dataset.table`
If to apply to sample data from your question - output is
Row company_id country total_revenue
1 1 Russia 1200.0
2 2 Croatia 600.0
3 2 Italy 600.0
4 3 USA 400.0
5 3 UK 400.0
6 3 Italy 400.0