Question

好吧，我有三张桌子：

购物车：

ID | Product | Quantity
1    S1FG      3
1    C0K0      1
1    SLM1      6
2    S1FG      2
2    S94A      2

产品：

Code | Price
S1FG   10.00
C0K0   8.00
SLM1   19.50
S94A   2.00

用户：

ID | Nickname
1    Mark
2    Steve

我想要这个：

Nickname | Products | Total
Mark       10         155.00
Steve      4          24.00

简而言之，我想要一个用户列表，其中包含购物车中的商品，商品数量以及商品价格总和。

我试过了：

SELECT DISTINCT b.Nickname, SUM(a.Quantity) as Products, SUM(a.Quantity*c.Price) as Total 
FROM Cart a 
INNER JOIN Users b ON (a.ID = b.ID) 
INNER JOIN Products c ON (a.Product = c.Code)

但它没有用......

我该怎么办？

Answer 1

您需要GROUP BY昵称，否则您只需获得一行：

SELECT DISTINCT b.Nickname, SUM(a.Quantity) as Products, SUM(a.Quantity*c.Price) as Total 
FROM Cart a 
INNER JOIN Users b ON (a.ID = b.ID) 
INNER JOIN Products c ON (a.Product = c.Code)
GROUP BY b.Nickname

使用内部联接从三个不同的表中选择内容

1 个答案: