Question

要构建报告，我必须选择一些有关所有客户上次交易状态的信息。到现在为止，这就是我得到的：

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 ）。似乎MySQL忽略了 HAVING 。

我尝试进行子选择，但它也不起作用。

谢谢你的回答。

Answer 1

在这里，您需要有一个子查询，它为表date_add上的每个id_order获取最新的ps_order_history。然后，子查询的结果会在原始表ps_order_history上重新连接，前提是它在两列上显示：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

Answer 2

要获取最后一个日期，您需要将其加入：

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
inner join (select o.id_customer, max(oh.date_add) as maxdate from ps_order_history h join ps_order o on h.id_order = o.id_order group by o.id_customer) omax on omax.id_customer = o.id_customer and o.date_add = omax.maxdate
WHERE s.id_lang =6
GROUP BY c.id_customer

您的having子句计算最大日期，然后在不等于0（大部分时间）时成功。

按ID分组有max（date_field）

2 个答案: