mysql - 按具有 max(date_field) 的 id 分组

Question

要构建报告，我必须选择一些关于我所有客户的最后交易状态的信息。到目前为止，这是我得到的:

SELECT c.firstname, c.lastname, d.product_name, o.payment, s.name, h.date_add
FROM ps_orders o
INNER JOIN ps_order_detail d ON d.id_order = o.id_order
INNER JOIN ps_customer c ON c.id_customer = o.id_customer
INNER JOIN ps_order_history h ON o.id_order = h.id_order
INNER JOIN ps_order_state_lang s ON s.id_order_state = h.id_order_state
WHERE s.id_lang =6
GROUP BY c.id_customer
HAVING MAX(h.date_add)

对于每个客户，此查询在我需要最后一个日期时选择第一个日期(字段 h.date_add)。看来 MySQL 忽略了 HAVING。

我试着做一个子选择，但它也不起作用。

感谢任何回答。

Answer 1

在这里，您需要有一个子查询，它为表 ps_order_history 上的每个 id_order 获取最新的 date_add。然后将子查询的结果连接回原始表 ps_order_history，前提是它处理两列:date_add 和 id_order。

SELECT  c.firstname, 
        c.lastname, 
        d.product_name, 
        o.payment, 
        s.name, 
        h.date_add
FROM    ps_orders o
        INNER JOIN ps_order_detail d ON d.id_order = o.id_order
        INNER JOIN ps_customer c ON c.id_customer = o.id_customer
        INNER JOIN ps_order_history h ON o.id_order = h.id_order
        INNER JOIN  
        (
            SELECT  id_order, MAX(date_add) max_date
            FROM    ps_order_history
            GROUP   BY id_order
        ) x ON  h.id_order = x.id_order AND
                h.date_add = x.max_date
        INNER JOIN ps_order_state_lang s ON s.id_order_state = h.id_order_state
WHERE   s.id_lang =6
GROUP   BY c.id_customer