How to sum the values of column on duplicate key? - mysql

Question

I have a table like this:
// 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 |
+----+--------+-------+-------+
Now I want to sum the numbers of value where both name and key are identical. So, I want this output:
// 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 |
+----+--------+-------+-------+
Is it possible to I do that?
Edit: How can I do that for insert?
// 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 |
+----+--------+-------+-------+
Inserting these rows:
+----+--------+-------+-------+
| 10 | jack | 1 | 5 |
+----+--------+-------+-------+
+----+--------+-------+-------+
| 11 | bert | 1 | 2 |
+----+--------+-------+-------+
What I want: (output)
// 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

You have to group by more columns.
select name, key, sum(value) from mytable group by name, key;

Answer 2

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

Answer 3

check this
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)
;
query used was
select min(id) id ,name,[key],sum(value) value from #testing_123 group by name,[key] order by 1
output after insert

Answer 4

For the first part (to get the id column in the way requested), you could work along:
INSERT INTO mynewtable
(id, name, `key`, `value`)
SELECT
MIN(id), name, `key`, SUM(`value`)
FROM mytable
GROUP BY name, `key`
;
Now, provided mynewtable is defined with a unique index on name and key like
CREATE TABLE mynewtable
(id INT, name VARCHAR(5), `key` INT, `value` INT, UNIQUE (name, `key`));
you'd get the requested result with
INSERT INTO mynewtable
(id, name, `key`, `value`)
VALUES
(10, 'jack', 1, 5),
(11, 'bert', 1, 2)
ON DUPLICATE KEY UPDATE `value` = `value` + VALUES(`value`)
;
Beware:
It requires the unique index on name and key to work.
It might not work correctly, if there are other unique indexes and/or a primary key on the same table as well.
NB:
Please try to avoid the use of reserved words such as value and key for, e.g., column names.