Question

我遇到一个问题，请在下面指出。

这是表格查询

-------------------------------------------
id    title    cate    query_id    point   |
-------------------------------------------
1     A        1       1           1       |
2     B        1       1           3       |
3     C        1       1           2       |
4     A        2       2           3       |
5     B        2       2           2       |
6     C        1       2           1       |
--------------------------------------------

如果我进行分组（分类，查询）并获得最高分

----------------------------
cate    query_id    point   |
----------------------------
1       1           3       |
2       2           3       |
1       2           1       |
----------------------------

但是我想通过这样的分类来获得最大点数的总和：

--------------
cate    point |
--------------
1         4   | 
2         3   |
--------------

我希望你能帮助我。

Answer 1

您可以使用如下所示的派生表子查询来生成汇总：

SELECT cate, SUM(point) AS point
FROM (
    SELECT cate, query_id, MAX(point) AS point
    FROM MyTable
    GROUP BY cate, query_id
) AS t
GROUP BY cate;

Answer 2

通过此操作您可以获得预期的结果

query::groupBy(cate,query_id)->sum(point)

Answer 3

首先，您需要使用分组依据（类别，查询）并获取cate，query_id，max（point）。

SELECT cate, query_id, MAX(point) AS point
FROM demo
GROUP BY cate, query_id

demo on dbFiddle

现在，您想从上述查询输出中通过分类获取点组总和。

SELECT p.cate, SUM(p.point) AS point
FROM (
    SELECT cate, query_id, MAX(point) AS point
    FROM demo
    GROUP BY cate, query_id
) AS p
GROUP BY cate;

demo on dbfiddle

如何获得所有最大列值的总和

3 个答案: