为什么我的 SQL SUM 不会为我的加入添加？

Question

所以我有代码可以将所有供应商付款汇总在一起，然后将其显示在降序列表中。

SELECT vendor_name, SUM(payment_total) AS payment_total
FROM Vendors  JOIN Invoices
     ON (Vendors.vendor_id = Invoices.vendor_id)
GROUP BY vendor_name, payment_total
ORDER BY payment_total DESC;

然而，它所做的只是制作一个重复的供应商名称列表以及刚刚列出的付款总额，而不是相加。我尝试使用 DISTINCT 但一直得到相同的结果。

Answer 1

删除 GROUP BY payment_total，因为您希望总计按供应商分组：

SELECT 
    vendor_name, 
    SUM(payment_total) AS payment_total
FROM 
    Vendors  
    JOIN Invoices ON Vendors.vendor_id = Invoices.vendor_id
GROUP BY 
    vendor_name
ORDER BY 
    SUM(payment_total) DESC

并按 SUM(payment_total) DESC

排序

Answer 2

您想要对每个供应商名称的总数求和，而不是像当前 group by 子句所示的每个供应商名称和总数。只需从中删除 total_payment 就可以了：

SELECT   vendor_name, SUM(payment_total) AS payment_total
FROM     Vendors 
JOIN     Invoices ON (Vendors.vendor_id = Invoices.vendor_id)
GROUP BY vendor_name
ORDER BY payment_total DESC;

为什么我的 SQL SUM 不会为我的加入添加？

why won't my SQL SUM add for my join?

sql

select

sum

inner-join