Two ways to use Count, are they equivalent?

Question

Is

SELECT COUNT(a.attr)
FROM TABLE a

equivalent to

SELECT B
FROM (SELECT COUNT(a.attr) as B
      FROM TABLE a)

I would guess no, but I'm not sure.

I'm also assuming the answer would be the same for functions like min, max, avg, correct?

EDIT:

This is all out of curiosity, I'm still new at this. Is there a difference between the value returned for the count of the following and the above?

SELECT B, C
FROM (SELECT COUNT(a.attr) as B, a.C
      FROM TABLE a
      GROUP BY c)

EDIT AGAIN: I looked into it, lesson learned: I should be awake when I try to learn about these things.

Answer 1

Technically, they are not the same, the first one is a simple select, the second one is a select with a sub select.
But every sane optimizer will generate the same execution plan for both of them.