创建一个查询以实现两个相同的结果

我想要获得包含教师，费用和佣金的月份列表。费用包含付给老师的分期付款和给予课程的费用。 Commision是'每课授课'和'月份价格'的总和。创建一个查询以实现两个相同的结果

模式：

CREATE TABLE contract 
    (`id` int, `teacher` varchar(64), `lesson_price` int, `lesson_price_commision` int, `month_price` int) 
; 

INSERT INTO contract 
    (`id`, `teacher`, `lesson_price`, `lesson_price_commision`, `month_price`) 
VALUES 
    (1, 'John', 50, 10, 0), 
    (2, 'Paul', 40, 15, 0), 
    (3, 'Meg', 0, 0, 800) 
; 

CREATE TABLE installment 
    (`id` int, `contract` int, `installment_price` int, `installment_date` date) 
; 

INSERT INTO installment 
    (`id`, `contract`, `installment_price`, `installment_date`) 
VALUES 
    (1, 1, 300, '2015-09-28'), 
    (2, 1, 400, '2015-09-30'), 
    (3, 3, 500, '2015-09-28') 
; 

CREATE TABLE lesson 
    (`id` int, `contract` int, `lesson_date` date) 
; 

INSERT INTO lesson 
    (`id`, `contract`, `lesson_date`) 
VALUES 
    (1, 1, '2015-08-16'), 
    (2, 3, '2015-09-01'), 
    (3, 2, '2015-09-02'), 
    (4, 1, '2015-09-06') 
;

我在两个查询成功了，但我必须将它们合并。

查询之一：

SELECT teacher, SUM(lesson_price_commision) AS commision, SUM(lesson_price) AS expense 
FROM contract 
JOIN lesson ON contract.id=lesson.contract 
WHERE MONTH(lesson_date) = 9 AND YEAR(lesson_date) = 2015 
GROUP BY teacher

查询二：

SELECT teacher, SUM(month_price) AS commision, SUM(installment_price) AS expense 
FROM installment 
JOIN contract ON contract.id=installment.contract 
WHERE MONTH(installment_date) = 9 AND YEAR(installment_date) = 2015 
GROUP BY teacher

我构造的本：

SELECT teacher, 
     (SUM(lesson_price_commision) + SUM(month_price)) AS commision, 
     (SUM(lesson_price)+SUM(installment_price)) AS expense 
FROM contract 
    JOIN lesson ON contract.id=lesson.contract 
    LEFT JOIN installment ON installment.contract = contract.id 
WHERE (MONTH(installment_date) = 9 AND YEAR(installment_date) = 2015) 
    OR (MONTH(lesson_date) = 9 AND YEAR(lesson_date) = 2015) 
GROUP BY teacher

和结果是：

teacher | comission | expense 
----------------------------- 
John | 40  | 1600 
Paul | 15  | null 
Meg  | 800  | 500

但我期待：

teacher | comission | expense 
----------------------------- 
John | 10  | 750 
Paul | 15  | 40 
Meg  | 800 | 500

小提琴：http://sqlfiddle.com/#!9/7247a/1

来源

2015-09-26 andrzej1_1

而结果应该是？请将所有问题都添加到您的问题中，因为链接可能会中断，尤其是SQLFiddle –

@juergend完成。 –

你有一个非常混乱的数据结构。我不太清楚不同实体应该代表什么。但是，以下内容会返回您期望的结果（请参阅here）：

SELECT c.teacher, (c.lesson_price_commision + c.month_price) as commission, 
     (c.lesson_price + coalesce(i.expense, 0)) as expense 
FROM contract c LEFT JOIN 
    (SELECT c.teacher, sum(installment_price) as expense 
     FROM lesson l JOIN 
      installment i 
      ON i.contract = l.contract join 
      contract c 
      ON i.contract = c.id 
     WHERE l.lesson_date >= '2015-09-01' and l.lesson_date < '2015-10-01' 
     GROUP BY c.teacher 
    ) i 
    ON c.teacher = i.teacher;

来源

2015-09-26 11:18:37

创建一个查询以实现两个相同的结果

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