SQL Query Combine Rows on ID

Question

I am trying to run a query on my quote history table and trying to get an understanding of our response time.

I have a table named status_history and I wish to return the date difference between two rows for the same quote.

I have the following query:

SELECT
    quote_number,
    status,
    date,
    DATEDIFF
    (hh,
    (SELECT dateEntered 
            FROM status_history 
            WHERE status = 'Submitted'),
    (SELECT dateEntered 
            FROM status_history 
            WHERE status = 'Accepted')) as hour_difference

FROM 
    status_history

WHERE 
    status in ('Submitted','Accepted')

I am trying to get the final query to output like this:

quote_number| hour_difference

I am having a hard time getting this to output the way I want, because each quoteid can have multiple rows, because it can have a status change multiple times. Like seen here:

quote_number |  status     |  date
---------------------------------------------------
1234         | Submitted   |  2014-05-12 00:00:00.000
1234         | Accepted    |  2014-05-13 00:00:00.000
1234         | Complete    |  2014-05-14 00:00:00.000
1234         | Incomplete  |  2014-05-15 00:00:00.000

Eventually, I would like to check for the time between all status changes, but just this for now should get me going.

Thanks again!

Answer 1

Does this do what you want?

SELECT quote_number, 
       DATEDIFF(hh,
                max(case when status = 'Submitted' then dateEntered end),
                max(case when status = 'Accepted' then dateEntered end)
               ) as hour_difference
FROM status_history
WHERE status in ('Submitted','Accepted')
GROUP BY quote_number;