mysql行转列列转行

CREATE TABLE sales (
    id INT AUTO_INCREMENT PRIMARY KEY,
    product VARCHAR(50),
    region VARCHAR(50),
    amount INT
);

INSERT INTO sales (product, region, amount) VALUES
('ProductA', 'North', 100),
('ProductA', 'South', 150),
('ProductB', 'North', 200),
('ProductB', 'South', 250);

SELECT 
    product,
    SUM(CASE WHEN region = 'North' THEN amount ELSE 0 END) AS North,
    SUM(CASE WHEN region = 'South' THEN amount ELSE 0 END) AS South
FROM sales
GROUP BY product;

CREATE TABLE products (
    id INT AUTO_INCREMENT PRIMARY KEY,
    product VARCHAR(50),
    feature1 VARCHAR(50),
    feature2 VARCHAR(50)
);

INSERT INTO products (product, feature1, feature2) VALUES
('ProductA', 'FeatureX', 'FeatureY'),
('ProductB', 'FeatureX', 'FeatureZ');

SELECT product, 'Feature1' AS feature, feature1 AS value FROM products
UNION ALL
SELECT product, 'Feature2' AS feature, feature2 AS value FROM products;