Sorry!! Failed in validation

Warning: Cannot modify header information - headers already sent by (output started at /var/www/html/Training/nomination/nomination.php:20) in /var/www/html/Training/nomination/nomination.php on line 21

Fatal error: Uncaught exception 'PDOException' with message 'SQLSTATE[22P02]: Invalid text representation: 7 ERROR: invalid input syntax for integer: ""' in /var/www/html/Training/nomination/nomination.php:25 Stack trace: #0 /var/www/html/Training/nomination/nomination.php(25): PDOStatement->execute(Array) #1 {main} thrown in /var/www/html/Training/nomination/nomination.php on line 25