Calculate monthly hours - sql-server

Question

CREATE TABLE EmpAttendance
(
EmpCode INT,
Time_In Time(5),
Time_Out Time(5),
DayDate date
)
INSERT INTO EmpAttendance VALUES (23, '08:30', '13:00', '2018-07-12');
INSERT INTO EmpAttendance VALUES (23, '13:45', '18:30', '2018-07-12');
INSERT INTO EmpAttendance VALUES (23, '09:15', '12:50', '2018-07-13');
INSERT INTO EmpAttendance VALUES (23, '14:02', '18:22', '2018-07-13');
INSERT INTO EmpAttendance VALUES (23, '08:30', '16:00', '2018-07-14');
INSERT INTO EmpAttendance VALUES (23, '08:45', '17:56', '2018-07-15');
INSERT INTO EmpAttendance VALUES (12, '09:15', '12:50', '2018-07-13');
INSERT INTO EmpAttendance VALUES (12, '14:02', '18:22', '2018-07-13');
INSERT INTO EmpAttendance VALUES (12, '08:30', '16:00', '2018-07-14');
I have this table structure that is storing the time in and out of specific employee on a specific day. I want to calculate the total number of hours that an employee was present for a whole month.
The query should accept 2 input date parameters and employee code and give the output as total hours.
I am able to get daily hours but I want to calculate monthly as well and can't figure out how.
SELECT EmpCode, [DayDate],
FirstIN = CAST(MIN(Time_In) AS TIME),
LastOUT = CAST(MAX(Time_Out) AS TIME),
HoursSpent = DATEDIFF(HOUR, CAST(MIN(Time_In) AS TIME), CAST(MAX(Time_Out) AS TIME)),
CONVERT(VARCHAR(6), Datediff(second, CAST(MIN(Time_In) AS TIME), CAST(MAX(Time_Out) AS TIME))/3600)
+ ':'
+ RIGHT('0' + CONVERT(VARCHAR(2), (Datediff(second, CAST(MIN(Time_In) AS TIME), CAST(MAX(Time_Out) AS TIME)) % 3600) / 60), 2)
+ ':'
+ RIGHT('0' + CONVERT(VARCHAR(2), Datediff(second, CAST(MIN(Time_In) AS TIME), CAST(MAX(Time_Out) AS TIME)) % 60) , 2 )
AS hoursSpent
FROM EmpAttendance
GROUP BY EmpCode, DayDate

Answer 1

just change it to GROUP BY DATEADD(MONTH, DATEDIFF(MONTH, 0, DayDate), 0)
SELECT EmpCode,
DATEADD(MONTH, DATEDIFF(MONTH, 0, DayDate), 0) as MonthDate,
--FirstIN = CAST(MIN(Time_In) AS TIME),
--LastOUT = CAST(MAX(Time_Out) AS TIME),
HoursSpent = DATEDIFF(HOUR, CAST(MIN(Time_In) AS TIME), CAST(MAX(Time_Out) AS TIME)),
CONVERT(VARCHAR(6), Datediff(second, CAST(MIN(Time_In) AS TIME), CAST(MAX(Time_Out) AS TIME))/3600)
+ ':'
+ RIGHT('0' + CONVERT(VARCHAR(2), (Datediff(second, CAST(MIN(Time_In) AS TIME), CAST(MAX(Time_Out) AS TIME)) % 3600) / 60), 2)
+ ':'
+ RIGHT('0' + CONVERT(VARCHAR(2), Datediff(second, CAST(MIN(Time_In) AS TIME), CAST(MAX(Time_Out) AS TIME)) % 60) , 2 )
AS HoursSpent
FROM EmpAttendance
-- add the condition here in where clause
WHERE DayDate >= #StartDate
GROUP BY EmpCode, DATEADD(MONTH, DATEDIFF(MONTH, 0, DayDate), 0)

Answer 2

Assuming your Time_In and Time_Out values always relate to the same day, you can just sum up the datediff in minutes for each day:
declare #t table(EmpCode int
,Time_In time(5)
,Time_Out time(5)
,DayDate date
);
insert into #t values(23, '08:30', '13:00', '2018-07-12'),(23, '13:45', '18:30', '2018-07-12'),(23, '09:15', '12:50', '2018-07-13'),(23, '14:02', '18:22', '2018-07-13'),(23, '08:30', '16:00', '2018-07-14'),(23, '08:45', '17:56', '2018-07-15'),(12, '09:15', '12:50', '2018-07-13'),(12, '14:02', '18:22', '2018-07-13'),(12, '08:30', '16:00', '2018-07-14');
select EmpCode
,dateadd(month,datediff(month,0,DayDate),0) as MonthGroup
,sum(datediff(minute,Time_In,Time_Out))/60 as HoursWorked
,sum(datediff(minute,Time_In,Time_Out))%60 as MinutesWorked
from #t
group by EmpCode
,dateadd(month,datediff(month,0,DayDate),0)
;
Output:
+---------+-------------------------+-------------+---------------+
| EmpCode | MonthGroup | HoursWorked | MinutesWorked |
+---------+-------------------------+-------------+---------------+
| 12 | 2018-07-01 00:00:00.000 | 15 | 25 |
| 23 | 2018-07-01 00:00:00.000 | 33 | 51 |
+---------+-------------------------+-------------+---------------+