从sql中的多个子表中选择答案

【问题标题】：select from multiple child tables in sql从sql中的多个子表中选择
【发布时间】：2016-04-14 17:16:47
【问题描述】：

我有 3 个表，1 个是父表和 2 个子表。第一个表包含所有订单号，其他 2 个子表包含订单号的订单详细信息

示例表 Order_master

order_id | order_date | order_status
-------------------------------------
   1     |  20-10-15  |  pending
------------------------------------
   2     |  10-11-15  |  closed
------------------------------------
   3     |  15-11-15  |  closed
------------------------------------
   4     |  25-12-15  |  pending
------------------------------------
   5     |  27-12-15  |  closed
------------------------------------

子表order_detail

-------------------------------------
id       | order_id | client_name
-------------------------------------
   1     |     1    |  Abc company
------------------------------------
   2     |     3    |  Test company

子表order_detail_cc

-------------------------------------
id       | order_id | client_name
-------------------------------------
   1     |     2    |  XYZ company
------------------------------------
   2     |     4    |  A2 company
------------------------------------
   3     |     5    |  B2 company
------------------------------------

现在我想得到结果

-------------------------------------
order_id | order_date | client_name
-------------------------------------
   1     |  20-10-15  |  Abc company
------------------------------------
   2     |  10-11-15  |  XYZ company
------------------------------------
   3     |  15-11-15  |  Test company
------------------------------------
   4     |  25-12-15  |  A2 company
------------------------------------
   5     |  27-12-15  |  B2 company
------------------------------------

请帮忙

【问题讨论】：

如果一个订单的details或details_cc中有很多条目怎么办？如果一个订单的两个表中都有条目怎么办？
你尝试过什么样的查询？

标签： mysql database join inner-join

【解决方案1】：

MySQL Union手册

SELECT Order_master.order_date, Order_master.order_date, u.client_name
FROM Order_master
JOIN (
    (SELECT order_id, client_name
    FROM order_detail)
    UNION
    (SELECT order_id, client_name
    FROM order_detail_cc)
) u ON Order_master.order_id = u.order_id

【讨论】：

【解决方案2】：

SELECT  order_id, order_date, client_name
FROM    order_detail
JOIN    order
USING   (order_id)
UNION ALL
SELECT  order_id, order_date, client_name
FROM    order_detail_cc
JOIN    order
USING   (order_id)

【讨论】：