T-SQL How to get SUM() from a subquery

I need fast answer (I can't check that code right now):

is that query works ? I need to get the total sum of a column values from the subquery, something like that:

  select su开发者_StackOverflow中文版m(select time from table) as sometimes group by sometimes

That doesnot work, try this

select sum(time) as sumtime from table

select avg(field_val)
from table1
where field_val in (
  SELECT TOP 3 field_val
  FROM table1
  ORDER BY field_val DESC
)

That isn't a subquery. You only have 1 from...