How to sum up time field in SQL Server

I have a column called "WrkHrs" and the data type is time(hh:mm:ss). I want to sum up the working hours for employees. But since it's time data type sql server doesn't let me use like sum(columnname).

How can I sum up the time data type fieled in sql query?

SELECT EmployeeID, minutes_worked = SUM(DATEDIFF(MINUTE, '0:00:00', WrkHrs)) 
FROM dbo.table 
-- WHERE ...
GROUP BY EmployeeID;

You can format it pretty on the front end. Or in T-SQL:

;WITH w(e, mw) AS
(
    SELECT EmployeeID, SUM(DATEDIFF(MINUTE, '0:00:00', WrkHrs)) 
    FROM dbo.table 
    -- WHERE ...
    GROUP BY EmployeeID
)
SELECT EmployeeID = e,
  WrkHrs = RTRIM(mw/60) + ':' + RIGHT('0' + RTRIM(mw%60),2)
  FROM w;

However, you're using the wrong data type. TIME is used to indicate a point in time, not an interval or duration. Wouldn't it make sense to store their work hours in two distinct columns, StartTime and EndTime?

In order to sum up the working hours for an employee you can calculate the difference between the shift start time and end time in minutes and convert it to readable format as following:

    DECLARE @StartTime      datetime = '08:00'
    DECLARE @EndTime        datetime = '10:47'
    DECLARE @durMinutes     int
    DECLARE @duration       nvarchar(5)

    SET @durMinutes = DATEDIFF(MINUTE, @StartTime, @EndTime)

    SET @duration = 
    (SELECT RIGHT('00' + CAST((@durMinutes / 60) AS VARCHAR(2)),2) + ':' + 
            RIGHT('00' + CAST((@durMinutes % 60) AS VARCHAR(2)), 2))

    SELECT @duration

The result : 02:47 two hours and 47 minutes

DECLARE @Tab TABLE
(
    data CHAR(5)
)

INSERT @Tab
SELECT '25:30' UNION ALL
SELECT '31:45' UNION ALL
SELECT '16:00'

SELECT STUFF(CONVERT(CHAR(8), DATEADD(SECOND, theHours + theMinutes, 
    '19000101'), 8), 1, 2, CAST((theHours + theMinutes) / 3600 AS VARCHAR(12)))
FROM (
    SELECT ABS(SUM(CASE CHARINDEX(':', data) WHEN 0 THEN 0 ELSE 3600 * 
        LEFT(data, CHARINDEX(':', data) - 1) END)) AS theHours,
    ABS(SUM(CASE CHARINDEX(':', data) WHEN 0 THEN 0 ELSE 60 * 
        SUBSTRING(data, CHARINDEX(':', data) + 1, 2) END)) AS theMinutes
    FROM @Tab
) AS d

For MS SQL Server, when your WorkingTime is stored as a time, or a varchar in order to sum it up you should consider that:

1) Time format is not supporting sum, so you need to parse it

2) 23:59:59.9999999 is the maximum value for the time.

So, the code that will work to get you the total number of WorkingHours:WorkingMinutes:WorkingSeconds would be the following:

SELECT 
 CAST(FORMAT((SUM((DATEPART("ss",WorkingTime) + DATEPART("mi",WorkingTime) * 60 + DATEPART("hh",WorkingTime) * 3600)) / 3600),'00') as varchar(max)) + ':' + 
  CAST(FORMAT((SUM((DATEPART("ss",WorkingTime) + DATEPART("mi",WorkingTime) * 60 + DATEPART("hh",WorkingTime) * 3600)) % 3600 / 60),'00') as varchar(max)) + ':' + 
  CAST(FORMAT((SUM((DATEPART("ss",WorkingTime) + DATEPART("mi",WorkingTime) * 60 + DATEPART("hh",WorkingTime) * 3600)) % 3600 % 60),'00') as varchar(max)) as WorkingTimeSum
FROM TableName