从多个表中添加总计

Question

我在 MySQL 上使用 Laravel 和 Eloquent。本质上，我试图从发票中获取结果，包括它们的“总”和“已支付”金额。

我有 4 张桌子：

发票

id int(10),
date_due date,
client_id int(10),
deleted_at datetime

invoices_items

id int(10),
invoice_id int(10),
price decimal(15,2),
quantity int(10)

invoices_payments（这是一个数据透视表，因为付款也可以应用于其他发票）

payment_id int(10),
invoice_id int(10),
amount decimal(15,2)

付款

id int(10),
payment_date date,
total decimal(15,2)

（还有其他字段但不相关）

根据其他一些答案和其他研究，我一直在使用这个查询：

select 
    `invoices`.*, 
    SUM(
        invoices_items.price * invoices_items.quantity
    ) as total ,
    SUM(
        invoices_payments.amount
    ) as paid
from 
    `invoices` 
    left join `invoices_items` on `invoices`.`id` = `invoices_items`.`invoice_id` 
    left join `invoices_payments` on `invoices`.`id` = `invoices_payments`.`invoice_id` 
where
    `invoices`.`deleted_at` is null
limit 
    25

我遇到的问题是结果总是只返回 1 行（测试数据库中有 5 张发票），并且“总计”或“已付款”的金额不正确。

我想补充一点，invoices_payments中可能没有任何记录

-- 解决方案--

这是最后的查询，以防有人遇到类似情况

select 
    `invoices`.*, 
    COALESCE(SUM(
        invoices_items.price * invoices_items.quantity
    ),0) as total, 
    COALESCE(SUM(invoices_payments.amount),0) as paid, 
    COALESCE(SUM(
        invoices_items.price * invoices_items.quantity
    ),0) - COALESCE(SUM(invoices_payments.amount),0) as balance 
from 
    `invoices` 
    left join `invoices_items` on `invoices`.`id` = `invoices_items`.`invoice_id` 
    left join `invoices_payments` on `invoices`.`id` = `invoices_payments`.`invoice_id` 
where 
    `invoices`.`deleted_at` is null 
group by 
    `invoices`.`id` 
order by 
    `balance` desc 
limit 
    25

Answer 1

在WHERE之后添加GROUP BY invoices.id