CREATE TABLE Has_Allergy (StuID NUMBER, Allergy VARCHAR2)
CREATE TABLE Student (StuID NUMBER, LName VARCHAR2, Fname VARCHAR2, Age NUMBER, Sex VARCHAR2, Major NUMBER, Advisor NUMBER, city_code VARCHAR2)
CREATE TABLE Allergy_Type (Allergy VARCHAR2, AllergyType VARCHAR2)

how old is each student and how many students are each age?
SELECT Age, COUNT(*) FROM Student GROUP BY Age
SELECT "Age", COUNT(*) FROM "Student" GROUP BY "Age"