and can you tell me, besides Alice and Zach, is there anyone else who is friends with Bob?
SELECT T1.name FROM Person AS T1 JOIN PersonFriend AS T2 ON T1.name   =   T2.name WHERE T2.friend   =   'Bob' and T1.name ! =  "Alice" and T1.name ! =  "Zach"
friends with Bob refers to WHERE clause filtering friend = 'Bob'; besides Alice and Zach, is there anyone else who is friends with refers to excluding Alice and Zach from the results with T1.name != 'Alice' AND T1.name != 'Zach';