SQL Querying of Data by grouping with only one main variable(Store) and finding the percentage of customers in other variable

Question

Tables - Store

Stores	Date	Customer_ID
A	01/01/2020	1111
C	01/01/2020	1111
F	02/01/2020	1234
A	02/01/2020	1111
A	02/01/2020	2222

Tables - Customer

Customer_ID	Age_Group	Income_Level
1111	26-30	Low
1234	25 and below	Mid
2222	31-60	High

I want to know how I can get this output.

Stores	Age_Group	Percentage_by_Age	Income_Level	Percentage_By_Income
A	25 and below	10	Low	80
A	25 and below	10	Mid	10
A	25 and below	10	High	10
A	26 - 30	42	Low	15
A	26 - 30	42	Mid	65
A	26 - 30	42	High	20
A	31 - 60	48	Low	30
A	31 - 60	48	Mid	50
A	31 - 60	48	High	20

I am using SQL to query from different tables. First I need to aggregate the number of customers by stores, then in each store, I want to find out how many customers visited Store A in a particular age group(25 and below), and how many of them are in which income level.

May I know how I can go about solving this query?

Thanks.

My current solution/thought process

SELECT 
    stores AS Stores,
    Age_Group AS Age,
    Income_Level AS Income
    COUNT(DISTINCT(Customer_ID)) AS Number_of_Customers
FROM tables JOIN tables....
GROUP BY Stores, Ages, Income;

And then manually calculating the percentages. But it doesn't seem right. Is there a way to produce an example output table using just SQL?

Answer 1

SELECT
    s.Stores AS Stores,
    c.age_group AS Age,
    a.income_level AS Affluence,
    CAST(COUNT(DISTINCT c.Customer_ID) AS numeric)*100/SUM(CAST(COUNT(DISTINCT c.Customer_ID) AS numeric)) OVER(PARTITION BY s.Stores ) AS Perc_of_Members

This is what I did in the end.