Question

我有一张这样的表：

// mytable
+----+--------+-------+-------+
| id |  name  |  key  | value |
+----+--------+-------+-------+
| 1  | jack   | 1     | 10    |
| 2  | peter  | 1     | 5     |
| 3  | jack   | 2     | 5     |
| 4  | ali    | 1     | 2     |
| 5  | jack   | 1     | 5     |
| 6  | jack   | 1     | 10    |
| 7  | bert   | 4     | 2     |
| 8  | peter  | 2     | 10    |
| 9  | bert   | 4     | 5     |
+----+--------+-------+-------+

现在我想总算value和name相同的key数。所以，我想要这个输出：

// mynewtable
+----+--------+-------+-------+
| id |  name  |  key  | value |
+----+--------+-------+-------+
| 1  | jack   | 1     | 25    |
| 2  | peter  | 1     | 5     |
| 3  | jack   | 2     | 5     |
| 4  | ali    | 1     | 2     |
| 7  | bert   | 4     | 7     |
| 8  | peter  | 2     | 10    |
+----+--------+-------+-------+

我可以这样做吗？

修改：如何为insert执行此操作？

// mytable
+----+--------+-------+-------+
| id |  name  |  key  | value |
+----+--------+-------+-------+
| 1  | jack   | 1     | 25    |
| 2  | peter  | 1     | 5     |
| 3  | jack   | 2     | 5     |
| 4  | ali    | 1     | 2     |
| 7  | bert   | 4     | 7     |
| 8  | peter  | 2     | 10    |
+----+--------+-------+-------+

插入这些行：

    +----+--------+-------+-------+ 
    | 10 | jack   | 1     | 5     |
    +----+--------+-------+-------+ 
    +----+--------+-------+-------+ 
    | 11 | bert   | 1     | 2     |
    +----+--------+-------+-------+

我想要的是：（输出）

// mynewtable
+----+--------+-------+-------+
| id |  name  |  key  | value |
+----+--------+-------+-------+
| 1  | jack   | 1     | 30    |
| 2  | peter  | 1     | 5     |
| 3  | jack   | 2     | 5     |
| 4  | ali    | 1     | 2     |
| 7  | bert   | 4     | 7     |
| 8  | peter  | 2     | 10    |
| 11 | bert   | 1     | 2     |
+----+--------+-------+-------+

Answer 1

您必须按更多列进行分组。

select name, key, sum(value) from mytable group by name, key;

Answer 2

按name, key分组

 select name, key, sum(value) as value 
 from mytable group by name,key

Answer 3

检查这个

CREATE TABLE #testing_123
    ([id] int, [name] varchar(5), [key] int, [value] int)
;

INSERT INTO #testing_123
    ([id], [name], [key], [value])
VALUES
    (1, 'jack', 1, 10),
    (2, 'peter', 1, 5),
    (3, 'jack', 2, 5),
    (4, 'ali', 1, 2),
    (5, 'jack', 1, 5),
    (6, 'jack', 1, 10),
    (7, 'bert', 4, 2),
    (8, 'peter', 2, 10),
    (9, 'bert', 4, 5)
;

使用的查询是

select min(id) id ,name,[key],sum(value) value from #testing_123 group by name,[key] order by 1

插入后

输出

Answer 4

对于第一部分（以请求的方式获取 id 列），您可以进行以下操作：

INSERT INTO mynewtable
    (id, name, `key`, `value`)
SELECT
  MIN(id), name, `key`, SUM(`value`)
FROM mytable
GROUP BY name, `key`
;

现在，只要在名称和键之类的上定义了 mynewtable

CREATE TABLE mynewtable
(id INT, name VARCHAR(5), `key` INT, `value` INT, UNIQUE (name, `key`));

您将获得请求的结果

INSERT INTO mynewtable
    (id, name, `key`, `value`)
VALUES
    (10, 'jack', 1, 5),
    (11, 'bert', 1, 2)
ON DUPLICATE KEY UPDATE `value` = `value` + VALUES(`value`)
;

当心：

它要求名称和键上的唯一索引才能起作用。
如果同一表上还存在其他唯一索引和/或主键，则它可能无法正常工作。

NB ：请尽量避免使用诸如列名之类的保留字，例如 value 和 key 。

如何对重复键上的列值进行求和？

4 个答案: