CREATE TABLE PersonFriend (friend VARCHAR2, name VARCHAR2)
CREATE TABLE Person (name VARCHAR2, gender VARCHAR2)

Find the female friends of Alice.
SELECT T2.friend FROM Person AS T1 JOIN PersonFriend AS T2 ON T1.name = T2.friend WHERE T2.name = 'Alice' AND T1.gender = 'female'
SELECT "T2"."friend" FROM "Person" "T1" JOIN "PersonFriend" "T2" ON "T1"."name" = "T2"."friend" AND "T2"."name" = 'Alice' WHERE "T1"."gender" = 'female'