Mysql 按发票金额和项目总数订购客户

我试图根据发票金额和发票价值的总和来订购我的客户。要获得发票的价值，我需要对两个表中的项目进行合计：产品和支持。结构是这样的：

我尝试了此查询，但不起作用：

SELECT 
    c.id, 
    c.name, 
    COUNT(i.id) as total_amount, 
    SUM(ip.value * ip.quantity) as total_products,
    SUM(sp.value) as total_support
FROM InVoice i
INNER JOIN Costumer c ON i.id_costumer = c.id
LEFT JOIN InVoice_Product ip ON ip.id_invoice = i.id
LEFT JOIN InVoice_Support sp ON sp.id_invoice = i.id
GROUP BY c.id, c.name
ORDER BY total_amount, total_products DESC

如果我执行查询时没有左连接，只查找发票金额，效果很好。。但是当我尝试添加连接时，结果与实际不符

我在这件事上被绊倒了

编辑：

篡改预期结果（总金额）：

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处理完整的查询：

我认为您必须使用不同的计数，并对产品和支持的总和进行求和

SELECT 
    c.id, 
    c.name, 
    COUNT(DISTINCT i.id) as invoices_count, 
    SUM(ip.value * ip.quantity) + SUM(is.value) as total_amount
FROM Invoice i
INNER JOIN Costumer c ON i.id_costumer = c.id
LEFT JOIN InVoice_Product ip ON ip.id_invoice = i.id
LEFT JOIN InVoice_Support sp ON sp.id_invoice = i.id
GROUP BY c.id, c.name
ORDER BY invoices_count, total_amount DESC

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试一试

我认为问题在于对可能为空的值进行数学运算。尝试一下：

SELECT
    c.id, 
    c.name, 
    COUNT(i.id) as total_amount, 
    SUM(IF(NOT ip.value IS NULL,ip.value * ip.quantity,0)) as total_products,
    SUM(IF(NOT is.value IS NULL,is.value,0)) as total_support
FROM Invoice i
INNER JOIN Costumer c ON i.id_costumer = c.id
LEFT JOIN InVoice_Product ip ON ip.id_invoice = i.id
LEFT JOIN InVoice_Support sp ON sp.id_invoice = i.id
GROUP BY c.id, c.name
ORDER BY total_amount, total_products DESC

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只需“联合”两个表和发票\产品和发票\支持，因为当前查询发现发票\ id在所有三个表（发票、发票\产品、发票\支持）中通用：

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你能提供一些示例数据和预期结果吗？如果你能分享sql fiddle，那就太遗憾了。。我编辑问题并分享结果。当查询包含联接和求和时，总金额会增加..我尝试。。total_支持和total_产品看起来不错，但total_金额不正确。。。工作！谢谢！：）

select c.id, c.name, count (inv_prod_support.id_invoice), sum(inv_prod_support*quantity) as total_products,
sum(inv_prod_support.value) as total_support from
(select id_invoice, value, 0 as quantity from invoice_support
union select id_invoice, value, quantity from invoice_product ) inv_prod_support, invoice i
inner join customer c on i.id_customer = c.id
inner join inv_prod_support on inv_prod_support.id_invoice = i.id_invoice
group by c.id, c.name
order by total_amount, total_products desc