Database: network_2
Question: Find Alice's friends of friends.
SQL: select distinct t4.name from personfriend as t1 join person as t2 on t1.name  =  t2.name join personfriend as t3 on t1.friend  =  t3.name join personfriend as t4 on t3.friend  =  t4.name where t2.name  =  'alice' and t4.name != 'alice'