SQL get number of hours on previous rows - sql

Question

I am working on a query that extracts information about a store opening and close time. This is the resultset:
RTL_LOC_ID TRANS_TYPCODE BEGIN_DATETIME
---------- ------------------------------ ---------------------------
2390 WORKSTATION_OPEN 14.10.01 09:53:43,121000000
2390 WORKSTATION_CLOSE 14.10.01 23:51:49,729000000
2390 WORKSTATION_OPEN 14.10.02 09:57:47,768000000
2390 WORKSTATION_CLOSE 14.10.02 23:47:00,120000000
2390 WORKSTATION_OPEN 14.10.03 09:47:38,949000000
2390 WORKSTATION_CLOSE 14.10.03 23:45:42,602000000
6 rows selected
This is the query:
SELECT RTL_LOC_ID,TRANS_TYPCODE, BEGIN_DATETIME
FROM TRN_TRANS
WHERE(trans_typcode = 'WORKSTATION_OPEN' OR trans_typcode='WORKSTATION_CLOSE')
AND BUSINESS_DATE BETWEEN '14.10.01 00:00:00' AND '14.10.03 00:00:00'
ORDER BY BUSINESS_DATE, BEGIN_DATETIME ASC;
So I need to calculate the number of hours between the opening and closing of the store and place that value into a new column. I would also like to put the result for the day in the same row instead of two separate lines for each day.

Answer 1

This answer assumes MySQL since the question was not tagged with Oracle to begin with. I'm leaving this answer here, since it might inspire someone with Oracle skills toward a solution...
Assuming a location always opens before it closes, a quick and dirty solution could look like this:
SELECT RTL_LOC_ID, DATE(BUSINESS_DATE),
MIN(BUSINESS_DATE) AS [OpenTime],
MAX(BUSINESS_DATE) AS [CloseTime]
FROM
TRN_TRANS
WHERE(trans_typcode = 'WORKSTATION_OPEN' OR trans_typcode='WORKSTATION_CLOSE')
AND BUSINESS_DATE BETWEEN '14.10.01 00:00:00' AND '14.10.03 00:00:00'
GROUP BY RTL_LOC_ID, DATE(BUSINESS_DATE)
ORDER BY DATE(BUSINESS_DATE)
Or if you want to be pedantic:
SELECT RTL_LOC_ID, DATE(BUSINESS_DATE),
MAX(CASE trans_typcode WHEN 'WORKSTATION_OPEN' THEN BUSINESS_DATE ELSE NULL END) AS [OpenTime],
MAX(CASE trans_typcode WHEN 'WORKSTATION_CLOSE' THEN BUSINESS_DATE ELSE NULL END) AS [CloseTime],
FROM
-- rest of query same as above --

Answer 2

Is this what you mean?
SELECT
TRN_TRANS.RTL_LOC_ID,
DATE_FORMAT(BEGIN_DATETIME ,'%Y-%m-%d') AS _date,
TIMEDIFF(closing_time.BEGIN_DATETIME , opening_time.BEGIN_DATETIME ) AS _hours
FROM TRN_TRANS
INNER JOIN
(
SELECT RTL_LOC_ID, BEGIN_DATETIME, DATE_FORMAT(BEGIN_DATETIME ,'%Y-%m-%d') as _date
FROM TRN_TRANS
WHERE TRANS_TYPCODE = 'WORKSTATION_OPEN'
) AS opening_time
ON
TRN_TRANS.RTL_LOC_ID = opening_time.RTL_LOC_ID
AND
DATE_FORMAT(TRN_TRANS.BEGIN_DATETIME ,'%Y-%m-%d') = opening_time._date
INNER JOIN
(
SELECT RTL_LOC_ID, BEGIN_DATETIME, DATE_FORMAT(BEGIN_DATETIME ,'%Y-%m-%d') as _date
FROM TRN_TRANS
WHERE TRANS_TYPCODE = 'WORKSTATION_CLOSE'
) AS closing_time
ON
TRN_TRANS.RTL_LOC_ID = closing_time.RTL_LOC_ID
AND
DATE_FORMAT(TRN_TRANS.BEGIN_DATETIME ,'%Y-%m-%d') = closing_time._date
GROUP BY TRN_TRANS.RTL_LOC_ID, _date, _hours