SQL report to get average amount of time for helpdesk closures Pin

Question

Hi, I've been asked to write a report which lists the average time it takes for a helpdesk job to be closed. There isn't a closed date as such, the table column is simply an audit date/time which can be for various tasks.
I need to use this column along with another which is an ID of the action. For example:
User     TaskID   Task    AuditDatetime
Bob        2    Opens job   1/8/2014 11:14:29
Bob        5    Closes job  2/8/2014 10:12:26
Joe        2    Opens job   2/8/2014 11:01:45
Bob        5    Closes job  3/8/2014 11:44:22
My SQL is very rusty, I'm sure the report is technically possible but I can't for the life of me figure out what the SQL is.
I'm aware of the SQL AVG function and also know I may need to GROUP BY the user. I'm thinking some kind of CASE statement perhaps but again I can't think of the SQL to achieve this...
Can anybody please help?

Answer 1

DECLARE @helpDesk TABLE (JobID INT, userName varchar(10), TaskID INT, Task VARCHAR(20), AuditDatetime DATETIME)
INSERT INTO @helpDesk (JobID, userName, TaskID, Task, AuditDatetime)
VALUES
(17, 'Bob', 2, 'Opens job', '8/1/2014 11:14:29'),
(17, 'Bob', 5, 'Closes job', '8/2/2014 10:12:26'),
(22, 'Joe', 2, 'Opens job', '8/2/2014 11:01:45'),
(22, 'Bob', 5, 'Closes job', '8/3/2014 11:44:22'),
(25, 'Bob', 1, 'Opens job', '8/4/2014 11:40:22'),
(25, 'Joe', 3, 'Assigned job', '8/5/2014 11:47:22'),
(25, 'Joe', 5, 'Closes job', '8/5/2014 11:49:22')
SELECT *, DATEDIFF(minute,h2.AuditDatetime,h.AuditDatetime)/60.0 AS hours
FROM @helpDesk h
INNER JOIN @helpDesk h2
ON h.jobID = h2.jobID
AND h2.task = 'opens job '
WHERE h.task = 'Closes Job'
As far as open Jobs go, you could flip it around, like this:
DECLARE @helpDesk TABLE (JobID INT, userName varchar(10), TaskID INT, Task VARCHAR(20), AuditDatetime DATETIME)
INSERT INTO @helpDesk (JobID, userName, TaskID, Task, AuditDatetime)
VALUES
(17, 'Bob', 2, 'Opens job', '8/1/2014 11:14:29'),
(17, 'Bob', 5, 'Closes job', '8/2/2014 10:12:26'),
(22, 'Joe', 2, 'Opens job', '8/2/2014 11:01:45'),
(22, 'Bob', 5, 'Closes job', '8/3/2014 11:44:22'),
(25, 'Bob', 1, 'Opens job', '8/4/2014 11:40:22'),
(25, 'Joe', 3, 'Assigned job', '8/5/2014 11:47:22'),
(25, 'Joe', 5, 'Closes job', '8/5/2014 11:49:22'),
(26, 'Joe', 5, 'Opens job', '8/5/2014 11:49:22')
SELECT *, DATEDIFF(minute,h.AuditDatetime,COALESCE(h2.AuditDatetime,GETDATE()))/60.0 AS hours
FROM @helpDesk h
LEFT OUTER JOIN @helpDesk h2
ON h.jobID = h2.jobID
AND h2.task = 'Closes job '
WHERE h.task = 'Opens Job'
and coalesce the current date in for a close date.