转置postgresql中的列-横向连接？

CREATE TABLE sales (
    product_id INT,
    month VARCHAR(10),
    amount DECIMAL(10, 2)
);

INSERT INTO sales (product_id, month, amount) VALUES
(1, 'January', 1000),
(1, 'February', 1500),
(2, 'January', 2000),
(2, 'February', 2500);

SELECT * FROM crosstab(
    'SELECT product_id, month, amount FROM sales ORDER BY 1, 2',
    'SELECT DISTINCT month FROM sales ORDER BY 1'
) AS ct(product_id INT, "January" DECIMAL(10, 2), "February" DECIMAL(10, 2));

CREATE TABLE customers (
    customer_id INT,
    customer_name VARCHAR(100)
);

CREATE TABLE orders (
    order_id INT,
    customer_id INT,
    order_date DATE
);

INSERT INTO customers (customer_id, customer_name) VALUES
(1, 'Alice'),
(2, 'Bob');

INSERT INTO orders (order_id, customer_id, order_date) VALUES
(101, 1, '2023-01-15'),
(102, 2, '2023-02-20');

SELECT c.customer_id, c.customer_name, o.order_id, o.order_date
FROM customers c
INNER JOIN orders o ON c.customer_id = o.customer_id;