编辑代码

CREATE DATABASE test;
use test;
CREATE TABLE order_details (
    customer_id int,
    pid int
    -- PRIMARY KEY (customer_id, pid) -- 设置联合主键
);

INSERT INTO order_details (customer_id, pid)
VALUES  (1, 101),
        (1, 102),
    (1, 103),
    (2, 101),
    (2, 101),
    (3, 104),
    (3, 105),
    (3, 106),
    (3, 107);

select * from order_details;

select customer_id,COUNT(DISTINCT pid) AS unique_products_purchased
from order_details
GROUP BY customer_id
HAVING  COUNT(DISTINCT pid) > 3;