LeetCode（数据库）- Drop Type 1 Orders for Customers With Type 0 Orders

-- 解决方案(1)
select distinct a.order_id, a.customer_id, a.order_type from Orders as a left join Orders as b
on a.customer_id = b.customer_id and a.order_type <> b.order_type
where b.order_type is null or b.order_type = 1
-- 解决方案(2)
WITH t0 AS(SELECT * FROM Orders WHERE order_type = 0)
SELECT * 
FROM Orders
WHERE order_type = 1 AND customer_id NOT IN (SELECT customer_id FROM t0)
UNION ALL
SELECT * FROM t0