mysql对某几列求和

CREATE TABLE sales (
    id INT AUTO_INCREMENT PRIMARY KEY,
    product_name VARCHAR(100),
    quantity INT,
    price DECIMAL(10, 2)
);

SELECT SUM(quantity) AS total_quantity, SUM(price) AS total_price
FROM sales;

SELECT SUM(quantity) AS total_quantity, SUM(price) AS total_price
FROM sales
WHERE quantity IS NOT NULL AND price IS NOT NULL;

SELECT SUM(COALESCE(quantity, 0)) AS total_quantity, SUM(COALESCE(price, 0)) AS total_price
FROM sales;

-- 创建索引
CREATE INDEX idx_quantity ON sales(quantity);
CREATE INDEX idx_price ON sales(price);

-- 分片查询
SELECT SUM(COALESCE(quantity, 0)) AS total_quantity, SUM(COALESCE(price, 0)) AS total_price
FROM sales
WHERE id BETWEEN 1 AND 10000;