MySQL查询组合来自多个表的总和

Question

我有以下查询试图生成所有客户端，他们的项目，花在每个项目上的时间，总开票金额和发票总数的列表。

SELECT 
    c.name as client, 
    p.name as project, 
    SUM(t.hours) as hours, 
    SUM(ci.amount) as invoice_amount, 
    COUNT(ci.id) as number_invoices 
FROM 
    projects p 
    INNER JOIN client_master c ON c.harvest_id = p.client_id 
    INNER JOIN timesheet t ON t.project_id = p.id 
    LEFT OUTER JOIN projects_contracts pc ON pc.project_id = p.id 
    INNER JOIN contracts_invoices ci ON ci.contract_id = pc.contract_id 
GROUP BY 
    c.name, 
    p.name 
ORDER BY 
    c.name, 
    p.name, 
    t.hours 

当我运行查询，在“时间”被正确地计算，但总和/对INVOICE_AMOUNT和number_invoices计数不被上下文加入到该项目，但在表发票的总数。如果我注释掉总和的一个（）的话，我得到了应有的价值，但是当他们都在不。

预期结果

客户端A，项目1项，1000，$ 10,000，2

客户端A，项目2，5000，$ 5,000，1个

客户端B，项目1，100，$ 3000，1个

实效

客户端A，项目1，1000，$ 150,000，20

客户端A，项目2，5000，$ 50,000，81

客户端B，项目1，100，$ 83000，12

I”我已经尝试搞乱了分组和加入陈述，但没有找到成功。有没有简单的我可以忽略或者我需要一个完全重写？

Answer 1

这可能不是最好的方式，但我敢打赌，它的工作原理

SELECT 
    c.name as client, 
    p.name as project, 
    t.hours as hours, 
    ci.amount as invoice_amount, 
    ci.count as number_invoices 
FROM 
    projects p 
    INNER JOIN client_master c 
     ON c.harvest_id = p.client_id 
    INNER JOIN (SELECT project_id, SUM(hours) AS hours FROM timesheet GROUP BY project_id) t 
     ON t.project_id = p.id 
    LEFT OUTER JOIN projects_contracts pc 
     ON pc.project_id = p.id 
    LEFT OUTER JOIN (SELECT contract_id, SUM(amount) AS amount, COUNT(DISTINCT id) AS count FROM contracts_invoices GROUP BY contract_id) ci 
     ON ci.contract_id = pc.contract_id 
GROUP BY 
    c.name, 
    p.name 
ORDER BY 
    c.name, 
    p.name, 
    t.hours 

Answer 2

由于发票依赖于合同，并且合同是可选的（左连接），所以 使得该连接也是左连接。

SELECT 
    c.name as client, 
    p.name as project, 
    SUM(t.hours) as hours, 
    SUM(ci.amount) as invoice_amount, 
    COUNT(ci.id) as number_invoices 
FROM 
    projects p 
    INNER JOIN client_master c 
     ON c.harvest_id = p.client_id 
    INNER JOIN timesheet t 
     ON t.project_id = p.id 
    LEFT JOIN projects_contracts pc 
     ON pc.project_id = p.id 
    LEFT JOIN contracts_invoices ci 
     ON ci.contract_id = pc.contract_id 
GROUP BY 
    c.name, 
    p.name 
ORDER BY 
    c.name, 
    p.name, 
    t.hours