CREATE TABLE allergy_type (allergy CLOB, allergytype CLOB)
CREATE TABLE has_allergy (stuid NUMBER, allergy CLOB)
CREATE TABLE student (stuid NUMBER, lname CLOB, fname CLOB, age NUMBER, sex CLOB, major NUMBER, advisor NUMBER, city_code CLOB)

Find the first name and gender of the student who has allergy to milk but not cat.
SELECT fname, sex FROM student WHERE stuid IN (SELECT stuid FROM has_allergy WHERE allergy = "Milk" EXCEPT SELECT stuid FROM has_allergy WHERE allergy = "Cat")
SELECT "fname", "sex" FROM "student" WHERE "stuid" IN (SELECT "stuid" FROM "has_allergy" WHERE "Milk" = "allergy" EXCEPT SELECT "stuid" FROM "has_allergy" WHERE "Cat" = "allergy")