我怎样才能使用group，inner join和sum？

Question

我有两张表：产品＆amp; 销售

产品

id- productname  -  grp

11    bmwblue       bmw
12    bmwwhite      bmw
13    audiblack     audi
14    audiwhite     audi

销售

 id   productid  amount

 1      11        2
 2      12        1
 x      13        5
 x      14        3

我该如何表现;

听觉8，宝马3？

Answer 1

SELECT grp,
       sum(amount) AS total_grp_amount
FROM products AS p
JOIN sales AS s ON p.id = s.product_id
GROUP BY grp

我猜你正在寻找这个。