Notice: Undefined index: _type in /volume1/web/Exam/home/view_board.php on line 16

Fatal error: Uncaught PDOException: SQLSTATE[42000]: Syntax error or access violation: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near '' at line 1 in /volume1/web/Exam/home/view_board.php:18
Stack trace:
#0 /volume1/web/Exam/home/view_board.php(18): PDOStatement->execute()
#1 {main}
  thrown in /volume1/web/Exam/home/view_board.php on line 18