MySQL 8.0

By using db<>fiddle, you agree to license everything you submit by Creative Commons CC0.

CREATE TABLE Appointment (id SERIAL PRIMARY KEY, AppointmentDate DATE);
CREATE TRIGGER check_AppointmentDate 
BEFORE INSERT
ON Appointment 
FOR EACH ROW
BEGIN
IF NEW.AppointmentDate < CURRENT_DATE THEN
    SIGNAL SQLSTATE '45000' 
           SET MESSAGE_TEXT = 'AppointmentDate cannot be set in the past.';
END IF;
END
INSERT INTO Appointment (AppointmentDate) SELECT CURRENT_DATE + INTERVAL 1 DAY;
INSERT INTO Appointment (AppointmentDate) SELECT CURRENT_DATE;
INSERT INTO Appointment (AppointmentDate) SELECT CURRENT_DATE - INTERVAL 1 DAY;
AppointmentDate cannot be set in the past.

SELECT * FROM Appointment;


id
AppointmentDate


1
2022-08-05

2
2022-08-04