Need to calculate overtime and regular hours - sql

Question

I have 1 table as attendance
|AttendanceresultId | AccountID | Intime | Outtime | ShiftID |
| 1 | 1234 | 2016-06-21 06:56:00 | NULL | 1 |
| 2 | 1234 | NULL | 2016-06-21 17:02:00 | 1 |
| 3 | 1234 | 2016-06-22 06:56:00 | NULL | 1 |
| 4 | 1234 | NULL | 2016-06-22 17:02:00 | 1 |
| 5 | 1235 | 2016-06-21 22:55:00 | NULL | 3 |
| 6 | 1235 | NULL | 2016-06-22 06:00:00 | 3 |
| 7 | 1235 | 2016-06-22 22:55:00 | NULL | 3 |
| 8 | 1235 | NULL | 2016-06-23 07:00:00 | 3 |
Another table is shift table
| ShiftId | Starttime | Endtime |
| 1 | 07:00:00.00 | 16:00:00.00 |
| 3 | 23:00:00.00 | 06:00:00.00 |
I want to calculate the total number of working hours and over time hours for an employee lets say,
Expected Output,
| AccountID | NormalHours | OvertimeHours |
| 1234 | 18:08 Hrs | 02:04 Hrs |
| 1235 | 14:10 Hrs | 01:00 Hrs |
I am newbie in sql server can any one suggest anything

Answer 1

I broke this into four Parts to adjust for the lack of the lag function in 2008:
1) Common Table Expression to organize the records (so as not to count on the identity field)
2) Calculates the total minutes worked and worked for overtime without using the lag function
3) I then summarize those minutes - and split them into hours and minutes.
4) I then format them.
That said, there are quite a few possible places where I think real world data might create issues.
Updated version that does not use the lag function
WITH TimeRecords (AccountID, InOutTime, Intime, OutTime, Shift,
RowNumber) AS
(SELECT att.AccountID, COALESCE(att.Intime,att.OutTime),
att.Intime, att.OutTime, att.Shift,
ROW_NUMBER() OVER(ORDER BY att.AccountID,
COALESCE(att.InTime, att.OutTime) )
FROM dbo.attendance att)
,
ShiftTime AS (
SELECT trecout.AccountID ,
trecin.InTime,
trecout.OutTime,
-- sh.EndTime ,
-- Number of Minutes for the entire shift
CASE WHEN trecout.OutTime IS NOT NULL
THEN DATEDIFF(mi,
trecin.InTime,
trecout.OutTime)
ELSE 0
END AS TotalTime ,
-- Number of Minutes for overtime
CASE WHEN trecout.OutTime IS NOT NULL
THEN DATEDIFF(mi, sh.EndTime,
CAST(trecout.OutTime AS TIME))
ELSE 0
END AS OverTime
FROM TimeRecords trecout
JOIN TimeRecords trecin
ON trecout.RowNumber -1 = trecin.RowNumber
JOIN dbo.ShiftID sh
ON trecout.[Shift] = sh.ShiftID
)
,
-- Summarize the data
ShiftTimeSum
AS ( SELECT st.AccountID ,
FLOOR(SUM(st.TotalTime - st.OverTime) / 60) AS RegularHours ,
SUM(st.TotalTime - st.OverTime) % 60 AS RegularMinutes ,
SUM(st.OverTime) / 60 AS OverTimeHours ,
SUM(st.OverTime) % 60 AS OverTimeMinutes
FROM ShiftTime st
GROUP BY st.AccountID
)
-- Now format
SELECT sts.AccountID ,
CAST(sts.RegularHours AS VARCHAR(5)) + ':'
+ RIGHT(CAST(( 100 + sts.RegularMinutes ) AS CHAR(3)), 2) AS RegularTime ,
CAST(sts.OverTimeHours AS VARCHAR(5)) + ':'
+ RIGHT(CAST(( 100 + sts.OverTimeMinutes ) AS CHAR(3)), 2) AS OverTime
FROM ShiftTimeSum sts;