Question

我正在尝试创建一个将由非洲大陆分组的sql，然后在2000年按降序排列每个大洲的总销售额。这就是我所做的：

SELECT SUM(price) AS SaleSum, continent, country 
FROM  fact as F, address as A, daterecord as D 
WHERE F.address = A.id and F.transactionDate=D.id and D.`year`=2000
GROUP BY continent, country
ORDER BY SaleSum DESC

并且结果是输出仅按总销售额的下降排序，并且非洲没有分组。我该如何处理这个问题？谢谢！

更新

以上似乎有点令人困惑。我期待的是按非洲大陆分组的国家总销售额的排序结果。这就是说，对于每个大陆，该大陆的县都需要根据总销售额进行分类。对不起造成的混乱。

Answer 1

首先，您应该学会使用正确的join语法。简单规则：永远不要在from子句中使用逗号。

其次，我认为你只需要order by中的两个键：

SELECT SUM(price) AS SaleSum, continent, country 
FROM fact F JOIN
     address A
     ON F.address = A.id JOIN
     daterecord D 
     ON F.transactionDate = D.id
WHERE D.`year`=2000
GROUP BY continent, country
ORDER BY continent, SaleSum DESC;

Answer 2

可能你需要使用HAVING子句

SELECT SUM(price) AS SaleSum, continent, country, d.year as year
FROM  fact as F, address as A, daterecord as D 
WHERE F.address = A.id and F.transactionDate=D.id 
GROUP BY continent, country, year
HAVING year = 2000
ORDER BY SaleSum DESC

Mysql Group by和order in降序为每个组

2 个答案: