best approach "Where In' or join

Hi,

I have 2 sets
Set1 has few UNIQUE items say workitem Ids 2,3,4

Set2 has multiple items say workitems Ids is 1,2,2,4,3,5,4,3,6,7,8

I need to look for Set1 in Set2 so i get 2,3,4 etc...

which is the best way

Set2 Left join Set1

OR

Select item from Set2 where item in (Set1)

I would suggest the Where In clause, unless you wish to have many rows appearing.

A join will join every record from set1 to every record in set2 where the values are equal.

Where IN will check the values of Set1 are present in Set2.