多个选择条件来自每个表

Question

所以我有桌子 ip_clients，ip_invoice_items，ip_invoice_item_amounts，ip_invoices，ip_payments，ip_tax_rates。

结构：

| ip_clients  | ip_invoice_items     | ip_invoice_item_amounts |
| ----------- | -------------------- | ----------------------- |
| client_id   | item_id              | item_amount_id          |
| client_name | invoice_id           | item_id                 |
|             | item_quantity        | item_total              |
|             | item_price           | item_discount           |
|             | item_discount_amount |                         |
| ----------- | -------------------- | ----------------------- |

| ip_invoices       | ip_payments    | ip_tax_rates     |
| ----------------- | -------------- | ---------------- |
| invoice_id        | payment_id     | tax_rate_percent |
| user_id           | invoice_id     |                  |
| invoice_status_id | payment_amount |                  |
| ----------------- | -------------- | ---------------- |

表和单元格中存储的内容：

ip_clients ：存储客户的地方

client_id: client unique id
client_name: the client name

ip_invoice_items ：发票项目存放的位置

item_id: unique item id
invoice_id: unique invoice id from ip_invoices
item_quantity: the item's quantity
item_price: the item's cost stored as double example (11.29)
item_discount_amount: the item's discount stored as double example (5.19)

ip_invoice_item_amounts ：付款的存储位置

item_amount_id: the unique the item's id
item_id: the unique item's id from ip_invoice_items
item_total: the total item cost is stored as double (50.01)
item_discount: the item discount is stored as double (30.49)

ip_invoices ：发票ID和用户ID

invoice_id: the unique invoice id
user_id: the unique user id from ip_clients
invoice_status_id: if this cell has number 4 means its paid

ip_payments ：付款ID为发票ID和付款金额

payment_id: the unique payment id
invoice_id: the unique invoice id from ip_invoice
payment_amount: the amount paid is stored as double (100.00)

ip_tax_rates ：包含税号百分比

tax_rate_percent: contains single number

工作原理：

1. 我使用所选项目金额和费用创建发票
2. 我从客户处插入付款以关闭发票。

问题

我想知道客户的余额，他需要支付多少钱 我希望得到客户名称，并且只有当他有未结发票（他拥有钱）时才能获得当前债务（余额）。
因此，查询应该能够查看已支付的发票ID，并且不计算这些金额，并且在余额结果中应添加税率。

我很抱歉我无法做到这一点我被卡住了，我甚至不知道我是否正确解释了因为这对我来说很复杂我请求帮助

这是结构https://pastebin.com/c3iYNMkq

Answer 1

首先，让我们找出某个客户的公开发票，其中包含每个客户的债务：

select ip_clients.client_id, sum(ip_invoice_items.item_quantity * ip_invoice_items.item_price) - sum(ip_payments.payment_amount) as debt
from ip_clients
join ip_invoices
on ip_clients.client_id = ip_invoices.user_id
join ip_invoice_items
on ip_invoices.invoice_id = ip_invoice_items.invoice_id
join ip_payments
on ip_invoices.invoice_id = ip_payments.invoice_id
group by ip_clients.client_id, ip_invoices.invoice_id
having sum(ip_invoice_items.item_quantity * ip_invoice_items.item_price) - sum(ip_payments.payment_amount) > 0

现在，让我们使用这些知识来获得总余额：

select ip_clients.client_name, sum(debt) as balance
from ip_clients
join
(
select ip_clients.client_id, sum(ip_invoice_items.item_quantity * ip_invoice_items.item_price) - sum(ip_payments.payment_amount) as debt
from ip_clients
join ip_invoices
on ip_clients.client_id = ip_invoices.user_id
join ip_invoice_items
on ip_invoices.invoice_id = ip_invoice_items.invoice_id
join ip_payments
on ip_invoices.invoice_id = ip_payments.invoice_id
group by ip_clients.client_id, ip_invoices.invoice_id
having sum(ip_invoice_items.item_quantity * ip_invoice_items.item_price) - sum(ip_payments.payment_amount) > 0
) t
on ip_clients.client_id = t.client_id
group by ip_clients.client_id, ip_clients.client_name

我不是100％确定我理解您的商业模式，因此您可能会略微改进查询，但您明白了。