SQL Efficiency: WHERE IN Subquery vs. JOIN then GROUP

Question

As an example, I want to get the list of all items with certain tags applied to them. I could do either of the following:

SELECT Item.ID, Item.Name
FROM Item
WH         


        

Answer 1

I think it would depend on how the optimizer handles them, it may even be the case that you end up with the same performance. Display execution plan is your friend here.