SQL Multiple GROUP BY - mysql

Question

I can't figure out the mysql query to extract the data I want from this table "timeEntry":
hours creationDate userId clientId projectId taskId
20 2012-02-18 1 1 1 1
40 2012-02-18 1 1 1 1
30 2012-02-21 2 1 1 1
20 2012-02-22 2 1 1 2
30 2012-02-22 2 1 1 2
80 2012-02-23 1 2 2 2
10 2012-02-23 3 2 2 2
15 2012-02-23 1 2 2 3
40 2012-02-23 1 2 4 1
And I would like to have this kind of result as another table, or csv/excel file or php array (where totalHours is the sum of the hours for a userId) for a given period of time, let say (between 2012-02-01 and 2012-02-25):
clientId projectId taskId userId totalHours
1 1 1 1 60
2 30
2 2 50
2 2 2 1 80
3 10
3 1 15
4 1 1 40
I guess I have to use multiple group by, I tried something like:
SELECT clientId, projectId, taskId, userId, sum(hours)
FROM `timeEntry`
WHERE date_creation >= "2012-02-01"
AND date_creation <= "2012-02-25"
GROUP BY clientId, projectId, taskId, userId;
But didn't work...
Thanks in advance.

Answer 1

Where needs to go before Group by.
If you want to filter by date before grouping, use the where clause you have but moved before the group by.
If you'd instead like to filter entire groups in or out, use a having:
...
Group by ...
Having max(date) <= someValue and min(date) >= someValue

Answer 2

SELECT clientId, projectId, taskId, userId sum(Hours) total_hours
FROM timeEntry
GROUP BY clientID, ProjectID, TaskID, userID;
You can use [with Rollup][1] to generate sub-aggregrates. if you want

Answer 3

Here is a simple solution. You need to group by all necessary fields
SELECT
t.clientId,
t.projectId,
t.taskId,
t.userId,
SUM(t.hours) AS Total
FROM test AS t
GROUP BY t.creationDate , t.userId , t.clientId , t.projectId , t.taskId
Fiddle Demo
OUTPUT:
clientId projectId taskId userId Total
____________________________________________________________
1 1 1 1 60
1 1 1 2 30
1 1 2 2 50
2 2 2 1 80
2 2 3 1 15
2 4 1 1 40
2 2 2 3 10