Which committees have delegates from both democratic party and liberal party?
CREATE TABLE election (Committee VARCHAR, Party VARCHAR); CREATE TABLE party (Party_ID VARCHAR, Party VARCHAR)
[SQL] SELECT T1.Committee FROM election AS T1 JOIN party AS T2 ON T1.Party = T2.Party_ID WHERE T2.Party = "Democratic" INTERSECT SELECT T1.Committee FROM election AS T1 JOIN party AS T2 ON T1.Party = T2.Party_ID WHERE T2.Party = "Liberal" [/SQL]