Select the last 2 hours on database (specific hours)

Sophia said:

the earlier minutes wasn't capture since it depend on the date time i run the script.

I think by this you mean that if the current time is 11:14 Solution 1 will literally return everything within the last 2 hours i.e. from 9:14 to 11:14 but what you actually want is everything from 09:00 to 11:00.

If so then @RamiroX is close. Try

SELECT [LoadingDateTime]
FROM
@Products where
DATEDIFF(hour, [LoadingDateTime], getdate()) <= 2
group by [LoadingDateTime]
order by [LoadingDateTime] asc

One other point:
- Don't use Select * if using Group By - list the columns explicitly. To be honest, this is true in general for good coding practice.

A slight variation on solution 2 which will let SQL use an index on your date column (if there is one):

DECLARE @Now datetime = GETDATE();
DECLARE @Max datetime = DateAdd(hour, DateDiff(hour, 0, @Now), 0);
DECLARE @Min datetime = DateAdd(hour, -2, @Max);

SELECT [LoadingDateTime]
FROM dbo.Products 
WHERE [LoadingDateTime] >= @Min And [LoadingDateTime] < @Max
GROUP BY [LoadingDateTime]
ORDER BY [LoadingDateTime] ASC;

Non-SARGable Predicates - Brent Ozar Unlimited®[^]
sql server - T-SQL datetime rounded to nearest minute and nearest hours with using functions - Stack Overflow[^]