Calculate the sum of fields in another table using MySQL SQL query

Question

I have a schema like this: User table with attributes "user_id" and "username" and orders table with attributes "customer_id" (FK of user_id) and "finalPrice" Database schema I want to get the highest price among all order combinations The user (basically the sum of all FinalPrice values ​​for the order where customer_id=user_id) can't quite figure out a solution so any support would be appreciated selectsum((selecto.fina

P粉710478990 · Answer

Based on your query You can't use SUM function like this but use internal SUM that's why it throws error like Subquery returns more than 1 row

SELECT  
u.user_id,
(SELECT SUM(o.final_price) FROM `order` o WHERE u.user_id=o.customer_id)
FROM 
user u 
GROUP BY u.user_id;