MySQL的加入三个表，项目的总和加入到主表

Question

我有三个MySQL表：

例如

• 的表菜单ID，姓名

• 乙表是CUSTOMER_ORDER ID，order_date

• C表为order_item ID，menu_item_id，customer_order_id，order_quantity

我尝试输出名称，总和（order_quantity）在本月

目前我有工作确定两个单独的查询，但第二个查询foreach循环，这似乎不是那么好内。

首先查询其输出所有的菜单项：

$results = $wpdb->get_results("SELECT * FROM menu WHERE post_id = $pid ORDER BY sort_order "); 

第二个查询将输出总每个月每个销售项目：

$total = $wpdb->get_col("SELECT SUM(oi.order_item_quantity) 
          from order_item as oi 
          INNER JOIN customer_order as ho ON ho.ID = oi.order_id 
          WHERE oi.order_item_id = $subC->ID AND YEAR(ho.order_date) = $current_year AND MONTH(ho.order_date) = $current_month "); 

我尝试这两个查询合并为一个查询，这整整一天，但仍然无法解决它，任何人都可以给我一些帮助。

更新

感谢刘若英。

Select m.name, m.name as name, sum(oi.order_item_quantity) as sold_monthly from menu as m left join order_item as oi on oi.order_item_id = m.ID left join cusomter_order as co on co.ID = oi.order_id where m.post_id = 110 group by m.ID, m.name 

这将输出

name     sold_monthly  
Sushi Lunch Special  NULL 
Sushi Lunch    19 
Sashimi Lunch   61 
jason     NULL 
egg roll    NULL 

如果我添加YEAR(co.order_date) = 2016 AND MONTH(co.order_date) = 9

我只得到

name     sold_monthly  
Sushi Lunch    7 
Sashimi Lunch   14 

我怎能寿司午餐特，杰森，蛋卷，该空项目，当我添加YEAR(co.order_date) = 2016 AND MONTH(co.order_date) = 9.

在这里，我尝试

(year(co.order_date) = 2016 and month(co.order_date) = 10) or sold_monthly is null 

这给我一个查询错误

更新 感谢刘若英再次

它的工作现在

(year(co.order_date) = 2016 and month(co.order_date) = 10) or co.order_date is null 

最终解决它，上当我改变时，有小错误business_id可能无法捕捉到我想要的结果，所以我将其添加到子查询中。

Select m.*, p.sold_monthly from menu as m left join (SELECT SUM(oi.order_item_quantity) as sold_monthly, oi.order_item_id as ID, oi.order_item_name from order_item as oi LEFT JOIN cusomter_order as ho ON ho.ID = oi.order_id WHERE ho.business_id = $pid AND (year(ho.order_date) = $current_year and month(ho.order_date) = $current_month) OR ho.order_date is NULL GROUP by oi.order_item_id)p on p.ID = m.ID where m.post_id = $pid 

Answer 1

所以你试图让每个post_id列表限制选定的月份。 以下查询将产生以下示例数据。

SELECT m.ID as ID, m.Name as Name, SUM(oi.order_quantity) as Quantity 
FROM menu as m 
LEFT JOIN order_item as oi ON oi.menu_item_id = m.ID 
LEFT JOIN customer_order as co ON co.ID = oi.customer_order_id 
WHERE m.post_id = 0 AND YEAR(co.order_date) = 2016 AND MONTH(co.order_date) = 9 OR co.order_date is NULL 
GROUP BY m.ID,m.Name,m.sort_order 
ORDER BY m.sort_order 

样本数据

SET SQL_MODE = "NO_AUTO_VALUE_ON_ZERO"; 
SET time_zone = "+00:00"; 

DROP TABLE IF EXISTS `customer_order`; 
CREATE TABLE `customer_order` (
    `ID` int(11) NOT NULL, 
    `order_date` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP 
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_german2_ci; 

TRUNCATE TABLE `customer_order`; 
INSERT INTO `customer_order` (`ID`, `order_date`) VALUES 
(1, '2016-09-06 00:00:00'), 
(2, '2016-09-13 00:00:00'), 
(3, '2016-08-09 00:00:00'), 
(4, '2016-09-19 00:00:00'); 

DROP TABLE IF EXISTS `menu`; 
CREATE TABLE `menu` (
    `ID` int(11) NOT NULL, 
    `sort_order` int(11) NOT NULL, 
    `post_id` int(11) NOT NULL, 
    `Name` varchar(20) COLLATE utf8_german2_ci NOT NULL 
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_german2_ci; 

TRUNCATE TABLE `menu`; 
INSERT INTO `menu` (`ID`, `sort_order`, `post_id`, `Name`) VALUES 
(2, 0, 0, 'Test 1'), 
(4, 1, 0, 'Test 2'), 
(5, 2, 0, 'Test 3'); 

DROP TABLE IF EXISTS `order_item`; 
CREATE TABLE `order_item` (
    `ID` int(11) NOT NULL, 
    `menu_item_id` int(11) NOT NULL, 
    `customer_order_id` int(11) NOT NULL, 
    `order_quantity` int(11) NOT NULL 
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_german2_ci; 

TRUNCATE TABLE `order_item`; 
INSERT INTO `order_item` (`ID`, `menu_item_id`, `customer_order_id`, `order_quantity`) VALUES 
(1, 2, 1, 1), 
(2, 2, 2, 3), 
(3, 4, 1, 1), 
(4, 4, 2, 4), 
(5, 2, 3, 3), 
(6, 4, 3, 1), 
(7, 2, 4, 4); 


ALTER TABLE `customer_order` 
    ADD PRIMARY KEY (`ID`); 

ALTER TABLE `menu` 
    ADD PRIMARY KEY (`ID`), 
    ADD KEY `idx_pid` (`post_id`); 

ALTER TABLE `order_item` 
    ADD PRIMARY KEY (`ID`), 
    ADD KEY `idx_coid` (`customer_order_id`), 
    ADD KEY `idx_miid` (`menu_item_id`); 


ALTER TABLE `customer_order` 
    MODIFY `ID` int(11) NOT NULL AUTO_INCREMENT, AUTO_INCREMENT=5; 
ALTER TABLE `menu` 
    MODIFY `ID` int(11) NOT NULL AUTO_INCREMENT, AUTO_INCREMENT=6; 
ALTER TABLE `order_item` 
    MODIFY `ID` int(11) NOT NULL AUTO_INCREMENT, AUTO_INCREMENT=8; 

ALTER TABLE `order_item` 
    ADD CONSTRAINT `CostomerOrderConstrain` FOREIGN KEY (`customer_order_id`) REFERENCES `customer_order` (`ID`), 
    ADD CONSTRAINT `MenuItemConstrain` FOREIGN KEY (`menu_item_id`) REFERENCES `menu` (`ID`); 

好运积分查询，让我知道它的工作。

更新：更新示例数据以重现实际问题。更新了解决方案查询。