SQL datetime comparison with current datetime

Question

I have a project which involves comparing a datetime field with the current date and time, and if the difference between them is 10 minutes, then I have to select some date. It involves complexity, like if the current date and time is a date greater than the field datetime . Does anyone has a simple solution to this?

Answer 1

This can be done very simply using DATEDIFF :

IF ( SELECT DATEDIFF(MINUTE, a.StartDate, GETDATE())
     FROM   TableA a) > 10
BEGIN
    SELECT  *
    FROM    TableB
END

This simply says that if the current time ( GETDATE() ) is more than 10 minutes past the StartDate on TableA , do something else.

Note that if a.StartDate is greater than GETDATE() (for whatever reason), the value of DATEDIFF will be negative - in which case, you simply change the comparison to > -10 .

EDIT from comments:

I want all the serverID which all didnt run in the last 10 mins

This can be trivially accomplished with the following:

SELECT  ServerID
FROM    TableA
WHERE   DATEDIFF(MINUTE, LastRunTime, GETDATE()) > 10

Here are a few "checks" you can do to see the behavior of DATEDIFF - the comment regarding only caring about minutes is incorrect, but jumping to larger intervals DAY , MONTH , etc. does cause some interesting behavior.

For example:

SELECT DATEDIFF(MONTH, '05/30/2016 08:10:00', '06/01/2016 08:05:00')

Returns 1 (month), despite being only 2 days apart. Similarly,

SELECT DATEDIFF(DAY, '05/30/2016 08:10:00', '06/01/2016 08:05:00')

Returns 2, despite the time not quite making it to the 2-day mark. Finally,

SELECT DATEDIFF(YEAR, '12/31/2016 08:10:00', '01/01/2017 08:05:00')

Returns 1 as well.

Hopefully this helps in your understanding of using DATEDIFF .