-- 创建表格
CREATE TABLE customers (
    id SERIAL PRIMARY KEY,
    name VARCHAR(100),
    total_spent INT
);

CREATE TABLE orders (
    id SERIAL PRIMARY KEY,
    customer_id INT,
    amount INT
);

-- 插入示例数据
INSERT INTO customers (name, total_spent)
VALUES ('Alice', 500), ('Bob', 1000), ('Charlie', 1500);

INSERT INTO orders (customer_id, amount)
VALUES (1, 100), (2, 200), (2, 300), (3, 200), (3, 500);

SELECT customers.name, SUM(orders.amount) AS total_amount
FROM customers
INNER JOIN orders ON customers.id = orders.customer_id
GROUP BY customers.name;

   name   | total_amount
---------+-------------
 Alice   |         100
 Bob     |         500
 Charlie |         700