如果没有记录，如何创建一个事件以删除表和另一个事件

Question

I am creating a bus table with an event to maintain th data. Is it possible to drop the table and the autoDelete event by DropBusEvent event if no records exist in the bus table?

        stt.execute("CREATE TABLE IF NOT EXISTS bus"
                + "(id INT(11) NOT NULL AUTO_INCREMENT PRIMARY KEY,"
                + "mac VARCHAR(30) NOT NULL UNIQUE,"
                + "route int(11) NOT NULL,"
                + "latitude FLOAT(10,6) NOT NULL,"
                + "longitude FLOAT(10,6) NOT NULL,"
                + "created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP)");

        stt.execute("CREATE EVENT IF NOT EXISTS  AutoDelete "
                + "ON SCHEDULE EVERY 3 MINUTE "
                + "DO "
                + "DELETE FROM bus WHERE created_at < (NOW() - INTERVAL 3 MINUTE)");

        // I tried this statement here but it does not work.
        stt.execute("CREATE EVENT IF NOT EXITS DropBusTable "
                + "Do "
                + "DROP TABLES IF EXISTS bus");

I am getting You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'EXITS DropBusTableDROP TABLES IF EXISTS bus' at line 1 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'EXITS DropBusTableDROP TABLES IF EXISTS bus' at line 1

Answer 1

You have a mistake in your syntax:

EXITS instead of EXISTS in the line

stt.execute("CREATE EVENT IF NOT EXITS DropBusTable "