Question

I have an orders table with a schema like this.

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

I’m trying to retrieve a list of each customers most recent order. The table can have multiple orders by a customer, and each order has a primary key of order_id.

Answer 1

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