How do I upload the sensor data from arduino into a database?
First you have to create the table in your MySQL database, like:

CREATE TABLE IF NOT EXISTS `table_log` (
  `log_id` int(11) NOT NULL AUTO_INCREMENT,
  `log_date` date NOT NULL,
  `log_time` time NOT NULL,
  `log_t1` float NOT NULL,
  `log_t2` float NOT NULL,
  `log_t3` float NOT NULL,
  `log_t4` float NOT NULL,
  `log_vbatt` float NOT NULL,
  PRIMARY KEY (`log_id`)
) ENGINE=MyISAM  DEFAULT CHARSET=latin1 COLLATE=latin1_general_ci AUTO_INCREMENT=1; 


You can execute it in your phpmyadmin page (or create the table manually there). Above we have columns for auto-increment id ('log_id' - necessary), date &amp; time, 4 temperature values and voltage value (modify these according your requirements).

Than the query to create a new record would be like this:

INSERT INTO `table_log` (`log_id`, `log_date`, `log_time`, `log_t1`, `log_t2`, `log_t3`, `log_t4`, `log_vbatt`) VALUES
    (0, '2016-03-04', '01:53:30', 1.0, 2.0, 3.0, 4.0, 3.0);


You need to create this string dynamically (with real values) and use instead of INSERT_SQL.