Compare difference between GETDATE() and Datetime2 in SQL Server

Question

I want to check the amount of hours difference there is between current time (GETDATE()) and StartTime.

This is what I have so far:

SELECT 
    CheckedOut, GETDATE() AS CurrentDateTime, StartTime
FROM 
    TimeRecordModels 
WHERE 
    CheckedOut = 0;

Also I want to make the bool CheckedOut true if the difference is higher than 15 hours and then set column name EndTime to GETDATE()

Answer 1

Use the DATEDIFF function.

SELECT CheckedOut, GETDATE() AS CurrentDateTime, StartTime,
       DATEDIFF(hour, StartTime, GETDATE()) AS HoursDifference
    FROM TimeRecordModels 
    WHERE CheckedOut = 0;

To accomplish your update:

UPDATE TimeRecordModels
    SET CheckedOut = 1,
        EndTime = GETDATE()
    WHERE DATEDIFF(hour, StartTime, GETDATE()) > 15
        AND CheckedOut = 0;