DECLARE @MyTable TABLE(Enters TIME(0), LeftTime TIME(0));
INSERT @MyTable VALUES('07:00:00', '15:45:00')
SELECT *, FORMAT(CAST(DATEDIFF(HOUR, Enters, LeftTime) AS int),'00')+':'+FORMAT(CAST(DATEDIFF(MINUTE, Enters, LeftTime)% 60 AS INT),'00') AS JobTime FROM @MyTable;
