Can I GROUP BY aggregate Function (Like SUM)

Hello,
I column that calculated at run time in insert , can i gruop by this column,the new one that not exist yetyes, with a derived table, but why would you want to?

please show an example, using sample data to illustrate|||this is my case:

i have a table with a column datetime (I use to record time of calls) , i want to create table that hold data for each hour, so i round the column and want to group by this column in the same time|||you can round a datetime? please show your query|||This is the Query of round datetime

DATEADD(Hour, DATEDIFF(Hour, 0, cdrCallDate), 0)

You can change [hour] to day , minutes , second , etc...|||yes, you can GROUP BY that expression :)

and you cannot use second, it causes an overflow

:)|||thanks man for this information