Linux, Apache, MySQL, PHP

$Authors = $_POST["Authors"];
$keywords = $_POST["keywords"];
$ID_Number = $_Post["ID_Number"];
$keyword = preg_split(";",'$POST_[keywords]',-1,PREG_SPLIT_NO_EMPTY)
mysql="INSERT INTO Keyword (Keyword, ID_Number) Values
(FOREACH '$keyword', '$POST[ID_Number]')";
if (!mysql_query($sql,$con)) {
  die('Error: ' . mysql_error());  }
echo "Table: Keyword Updated";
$author = preg_split(";",'$POST_[Authors]',-1,PREG_SPLIT_NO_EMPTY)
mysql="INSERT INTO Author (Author, ID_Number) Values
(FOREACH '$author', '$POST[ID_Number]')";
if (!mysql_query($sql,$con)) {
  die('Error: ' . mysql_error());}
echo "Table: Author Updated";

$file = "output.txt";//file to write to
$f = fopen($file, 'w');//open file for writing
$date = date("G:i:s A");//gets the server time with the format: 24:00:00 AM
fwrite($f, $date);//write to file
fclose($f);//close file after writing

$date = date("G:i:s:u");