Are these two queries the same - GROUP BY vs. DISTINCT?

Question

These two queries seem to return the same results. Is that coincidental or are they really the same?

1.

SELECT t.ItemNumber,
  (SELECT TOP 1 ItemDes         


        

Answer 1

Since you're not using any aggregate functions, SQL Server should be smart enough to treat the GROUP BY as a DISTINCT.

You may also be interested in checking out the following Stack Overflow post for further reading on this topic:

• Is there any difference between Group By and Distinct?