CREATE TABLE Participants_in_Events (Event_ID NUMBER, Participant_ID NUMBER)
CREATE TABLE Services (Service_ID NUMBER, Service_Type_Code CHAR)
CREATE TABLE Participants (Participant_ID NUMBER, Participant_Type_Code CHAR, Participant_Details VARCHAR2)
CREATE TABLE Events (Event_ID NUMBER, Service_ID NUMBER, Event_Details VARCHAR2)

Please draw a histogram to show the total number of participants in each type code, list X-axis from low to high order.
SELECT Participant_Type_Code, COUNT(Participant_Type_Code) FROM Participants GROUP BY Participant_Type_Code ORDER BY Participant_Type_Code
SELECT "Participant_Type_Code", COUNT("Participant_Type_Code") FROM "Participants" GROUP BY "Participant_Type_Code" ORDER BY "Participant_Type_Code"