MYSQL Select using Left Join, Count, Group by - mysql

Question

I have this query:
SELECT c.`id`, w.`qty`, COUNT(c.`id`) AS pieces, c.`location`
FROM `control` AS c
LEFT JOIN `warehouse` AS w ON w.`id` = c.`id`
WHERE c.`code` = '40'
GROUP BY c.`id`
I have these tables:
`control` c `warehouse` w
+----+--------+------+----------+ +------+-------+
| id | pieces | code | location | | id | qty |
+----+--------+------+----------+ +------+-------+
| 112| 112-1 | 40 | london | | 112 | 3 |
| 112| 112-2 | 40 | london | | 113 | 3 |
| 112| 112-3 | 40 | london | | 114 | 1 |
| 113| 113-1 | 40 | italy | | 115 | 1 |
| 113| 113-2 | 40 | italy | +--------------+
| 113| 113-3 | 40 | italy |
| 114| 114-1 | 41 | france |
| 115| 115-1 | 41 | france |
| 112| 112-1 | 40 | germany |
| 112| 112-2 | 40 | germany |
| 112| 112-3 | 40 | germany |
| 113| 112-1 | 40 | russia |
| 113| 112-2 | 40 | russia |
| 113| 112-3 | 40 | russia |
| 112| 112-1 | 40 | poland |
| 112| 112-2 | 40 | poland |
| 112| 112-3 | 40 | poland |
+-------------------------------+
Im getting this:
actual output
+-----+-----+--------+----------+
| id | qty | pieces | location |
+-----+-----+--------+----------+
| 112 | 3 | 9 | poland |
| 113 | 3 | 6 | russia |
+-------------------------------+
I'm trying to get this result:
desired output
+-----+-----+--------+----------+
| id | qty | pieces | location |
+-----+-----+--------+----------+
| 112 | 3 | 3 | london |
| 113 | 3 | 3 | italy |
| 112 | 3 | 3 | germany |
| 113 | 3 | 3 | russia |
| 112 | 3 | 3 | poland |
+-------------------------------+
Is possible this result? maybe tweaking my query?
I tried without GROUP BY but in that case i just get 1 row totalizing pieces.

Answer 1

If you want to separate the different locations to different rows, you need to add that column to the group by clause:
SELECT c.`id`, w.`qty`, COUNT(c.`id`) AS pieces, c.`location`
FROM `control` AS c
LEFT JOIN `warehouse` AS w ON w.`id` = c.`id`
WHERE c.`code` = '40'
GROUP BY c.`id`, c.`location`
-- Here ---------^

Answer 2

I suspect that you just need to add qty and location to the group by clause:
SELECT c.`id`, w.`qty`, COUNT(*) AS pieces, c.`location`
FROM `control` AS c
LEFT JOIN `warehouse` AS w ON w.`id` = c.`id`
WHERE c.`code` = '40'
GROUP BY c.`id`, w.`qty`, c.`location`
Starting MySQL 5.7, it is mandatory to list all-non aggregated columns in the group by clause (unless you change default sql option ONLY_FULL_GROUP_BY); most other databases also implement this constraint. I would recommend getting used to it...
Side notes:
COUNT(c.id) is better written COUNT(*), since id seems like a not nullable column
generally spearking, you shoud avoid using backticks around table and column names unless when absolutly necessary.