Select values that meet different conditions on different rows?

Question

This is a very basic query I can\'t figure out....

Let\'s say I have a two column table like this:

userid  |  roleid
--------|--------
   1    |    1         


        

Answer 1

select userid from userrole where userid = 1
intersect
select userid from userrole where userid = 2
intersect
select userid from userrole where userid = 3

Won't this solve the problem? How good a solution is this on typical Relational DBs? Will query optimizer auto optimize this?