Question

我有一个带有这样的架构的订单表。

CREATE TABLE orders (
    order_id        int NOT NULL AUTO_INCREMENT,
    customer_id     int unsigned NOT NULL DEFAULT 0,
    order_date      int NOT NULL
)

我正在尝试检索每个客户最近订单的列表。该表可以由客户订购多个订单，每个订单的主键为order_id。

Answer 1

当您对AUTO_INCREMENT使用order_id时，每order_id customer_id最高Select customer_id, Max( order_id ) max_order_id From orders Group By customer_id应该是最新的：

order_id

如果您需要该行的所有列，则需要加入子选择（已修改以不依赖Select o.customer_id, o.order_id, o.order_date From orders o Join ( Select customer_id, Max( order_date ) max_order_date From orders Group By customer_id ) x On ( x.customer_id = c.customer_id AND x.max_order_date = o.order_date )）：

{{1}}

Answer 2

select o.*
from (
    select customer_id, max(order_date) as MaxOrderDate
    from orders
    group by customer_id
) om
inner join order o on om.customer_id = o.customer_id and om.MaxOrderDate = m.order_date

Answer 3

SELECT * FROM orders WHERE (customer_id, order_date) = (select customer_id, max(order_date) from orders group by customer_id)

创建一个查询以检索Mysql中的某些行

3 个答案: