I am trying to add hours quoted per machine. I have to look at three tables to get the correct and most recent data. I was able to get a list of the hours I need to add.

However, I tried all kinds of ways to use a SUM() function but it always gives me aggregate errors.

Here is the SQL Code:

```
SELECT 
(SELECT TOP 1 change.hours 
    FROM change WHERE change.id = part.id
    ORDER BY change.timeStamp DESC) as 'Hours'

FROM change 
INNER JOIN part ON (part.id = change.id)
INNER JOIN  completed ON (part.id = completed.id) 

WHERE part.id NOT IN (SELECT completed.id FROM completed WHERE completed.completed = 1) 
and (SELECT TOP 1 change.machine FROM change WHERE part.id = change.id ORDER BY change.timeStamp DESC ) = :machine

GROUP BY change.id, part.id

```

**I basically need to single-cell result that will add all the hours per machine. The result will be displayed on GUI.**

**RESULT SHOULD BE**
Machine 1 has to be 12 hours
Machine 2 has to be 18 hours
Machine 3 has to be 18 hours

TABLES
======

part
----

| id | number | description | job |
| --- | --- | --- | --- |
| 14 | 40023-10-100-10-03 | Base | 40023 |
| 15 | 40023-10-200-10-03 | Base | 40023 |
| 16 | 40024-10-100-10-01 | sensor bracket | 40024 |
| 17 | 40024-10-100-10-02 | Side | 40024 |
| 18 | 40025-10-100-10-01 | Conveyor hold | 40025 |
| 19 | 40025-10-200-00-01 | Part | 40025 |
| 20 | 40026-10-400-00-01 | Motor Mount | 40026 |
| 21 | 40026-10-200-10-10 | Delta arms | 40026 |
| 22 | 40023-10-200-10-03 | Base | 40023 |

change
------

| id | qty | hours | machine | operator | startTime | stopTime | completed | date | timeStamp |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 14 | 0 | 0 | 2 | 2 | NULL | NULL | False | NULL | 2021-10-28 00:00:00.000 |
| 15 | 0 | 0 | 4 | 3 | NULL | NULL | False | NULL | 2021-10-28 11:01:41.427 |
| 19 | 0 | 0 | 3 | 1 | NULL | NULL | False | NULL | 2021-10-28 11:10:50.730 |
| 18 | 0 | 0 | 2 | 3 | NULL | NULL | False | NULL | 2021-10-28 11:13:46.213 |
| 16 | 3 | 2.5 | 2 | 2 | NULL | NULL | False | 2021-10-27 | 2021-10-28 13:41:12.393 |
| 16 | 3 | 2.5 | 2 | 2 | NULL | NULL | False | 2021-10-27 | 2021-10-28 13:41:12.393 |
| 15 | 1 | 9 | 3 | 3 | NULL | NULL | True | 2021-10-29 | 2021-10-28 21:38:44.883 |
| 14 | 0 | 0 | 1 | 1 | NULL | NULL | False | NULL | 2021-11-01 10:36:43.223 |
| 14 | 0 | 0 | 1 | 1 | NULL | NULL | False | NULL | 2021-11-01 10:37:47.153 |
| 16 | 1 | 0.5 | 2 | 2 | NULL | NULL | False | 2021-11-01 | 2021-11-01 11:12:06.840 |
| 21 | 0 | 0 | 1 | 1 | NULL | NULL | False | NULL | 2021-11-01 11:45:30.050 |
| 20 | 0 | 0 | 2 | 3 | NULL | NULL | False | NULL | 2021-11-10 10:44:00.000 |
| 23 | 0 | 0 | 0 | 0 | NULL | NULL | True | 2021-11-02 | 2021-11-02 16:26:18.583 |
| 16 | 1 | 1 | 2 | 2 | NULL | NULL | False | 2021-11-01 | 2021-11-01 11:03:44.160 |
| 17 | 0 | 0 | 2 | 2 | NULL | NULL | False | NULL | 2021-10-28 11:25:03.967 |
| 17 | 0 | 0 | 1 | 1 | NULL | NULL | False | NULL | 2021-11-01 10:40:36.850 |
| 17 | 0 | 0 | 1 | 1 | NULL | NULL | False | NULL | 2021-11-01 10:42:56.350 |
| 22 | 0 | 0 | 3 | 2 | NULL | NULL | False | NULL | 2021-11-02 11:58:08.360 |
| 17 | 0 | 0 | 1 | 2 | NULL | NULL | False | NULL | 2021-11-01 10:43:44.273 |
| 14 | 0 | 0 | 1 | 1 | NULL | NULL | False | NULL | 2021-11-01 10:44:23.440 |
| 14 | 0 | 0 | 1 | 1 | NULL | NULL | False | NULL | 2021-11-02 12:57:06.810 |

change
------

| id | hours | qty | machine | operator | notes | rush | timeStamp |
| --- | --- | --- | --- | --- | --- | --- | --- |
| 14 | 2 | 3 | 2 | 1 |  | False | 2021-10-28 10:48:54.910 |
| 15 | 10 | 1 | 3 | 2 |  | False | 2021-10-28 10:49:47.643 |
| 16 | 7 | 10 | 2 | 3 | Need material | True | 2021-10-28 10:50:33.880 |
| 17 | 4 | 2 | 1 | 1 |  | False | 2021-10-28 00:00:00.000 |
| 18 | 5 | 1 | 2 | 2 |  | False | 2021-10-28 10:53:15.470 |
| 19 | 8 | 3 | 3 | 3 |  | False | 2021-10-28 11:10:50.573 |
| 14 | 3 | 4 | 1 | 1 | waiting for mills | False | 2021-10-29 08:12:00.000 |
| 17 | 4 | 2 | 1 | 1 |  | True | 2021-11-01 10:40:36.707 |
| 17 | 4 | 2 | 1 | 1 |  | True | 2021-11-01 10:42:56.150 |
| 16 | 8 | 10 | 2 | 3 | Need material | False | 2021-11-01 10:43:29.930 |
| 17 | 4 | 2 | 1 | 2 |  | False | 2021-11-01 10:43:44.047 |
| 14 | 3 | 4 | 1 | 1 |  | False | 2021-11-01 10:44:23.317 |
| 20 | 2 | 4 | 2 | 3 |  | False | 2021-11-01 11:44:10.257 |
| 21 | 5 | 3 | 1 | 1 | Need material | True | 2021-11-01 11:45:29.927 |
| 22 | 10 | 1 | 3 | 2 |  | False | 2021-11-02 11:58:08.220 |
| 14 | 3 | 4 | 1 | 1 |  | True | 2021-11-02 12:57:06.683 |
| 14 | 4 | 2 | 1 | 1 | waiting for bits | False | 2021-10-29 00:00:00.000 |
| 14 | 3 | 4 | 1 | 1 | wrong mills came. Need to order another ones | False | 2021-11-01 10:36:42.997 |
| 14 | 3 | 4 | 1 | 1 | wrong mills came. Need to order another ones | False | 2021-11-01 10:37:46.983 |