Get aggregated average values joining a second table and display them next to each value in first table

Michi :

I have two tables which you can also find in the SQL fiddle:

CREATE TABLE Sales (
    Product_ID VARCHAR(255),
    Category_ID VARCHAR(255),
    Sales_Value VARCHAR(255),
    Sales_Quantity VARCHAR(255)
);
INSERT INTO Sales
(Product_ID, Category_ID, Sales_Value, Sales_Quantity)
VALUES 
("P001", "C001", "500", "200"),
("P002", "C001", "600", "100"),
("P003", "C002", "300", "250"),
("P004", "C002", "900", "400"),
("P005", "C002", "800", "600"),
("P006", "C003", "200", "150"),
("P007", "C003", "700", "550");


CREATE TABLE Categories (
    Category_ID VARCHAR(255),
    Category_Name VARCHAR(255)
);
INSERT INTO Categories
(Category_ID, Category_Name)
VALUES 
("C001", "Fashion"),
("C002", "Sport"),
("C003", "Shoes");

The first table contains the Sales for each product.
The second table contains the Categories.

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Now, I want to display all products and the average_sales_price_per_category next to each product.
The result should look like this:

Product_ID      Category      average_sales_price_per_category
P001             Fashion               3.66
P002             Fashion               3.66
P003             Sport                 1.60
P004             Sport                 1.60
P005             Sport                 1.60
P006             Shoes                 1.28
P007             Shoes                 1.28

I tried to go with the solution from this question but I think the OVER clause is not available in my MySQL version:

SELECT 
s.Product_ID, 
c.Category_Name,
((SUM(s.Sales_Value * s.Sales_Quantity) over (partition BY c.Category_ID) /
SUM(s.Sales_Value) over (partition BY c.Category_ID)) as average_sales_price
FROM Sales s
JOIN Categories c ON c.Category_ID = s.Category_ID;

Error:

check the manual that corresponds to your MySQL server version for the right syntax to use near 'over (partition BY c.Category_ID) / SUM(s.Sales_Value) over (partition BY c.Cate' at line 4

What other SQL can I use to get the expected result?

Yogesh Sharma :

For older version, you can use correlated sub-query :

SELECT s.Product_ID, c.Category_Name,
       (SELECT SUM(SS.Sales_Value) / SUM(SS.Sales_Quantity)
        FROM Sales SS 
        WHERE SS.Category_ID = S.Category_ID
       ) AS average_sales_price
FROM Sales s JOIN 
     Categories c 
     ON c.Category_ID = s.Category_ID;

Here is SQL Fiddle.