CREATE TABLE Allergy_Type (Allergy VARCHAR2, AllergyType VARCHAR2)
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)

How many students are affected by each allergy type Visualize by bar chart, could you display total number in descending order please?
SELECT AllergyType, COUNT(*) FROM Has_Allergy AS T1 JOIN Allergy_Type AS T2 ON T1.Allergy = T2.Allergy GROUP BY T2.AllergyType ORDER BY COUNT(*) DESC
SELECT "AllergyType", COUNT(*) FROM "Has_Allergy" "T1" JOIN "Allergy_Type" "T2" ON "T1"."Allergy" = "T2"."Allergy" GROUP BY "T2"."AllergyType" ORDER BY COUNT(*) DESC