$re = '/(.*)\w\w_\w\w(?:.*?)(?:(?:[&?]\w+=\d+|%\w*)*?(\?Id=\d+)(?:.*))?/m';
$str = 'http://www.example.com/myplan/mp/public/pl_be?Id=543543×tamp=06280435435
http://www.example.com/course/df/public/pl_de%27?Id=454354×tamp=0628031746
http://www.example.com/book/rg/public/pl_fo?Id=4445577×tamp=0628031734
http://www.example.com/trip/tr/public/pl_ds&oisefejwf=02389283?anothaone=230023?somethingelse=2093432?Id=454354×tamp=06280314546
http://www.example.com/trip/tr/public/pl_ds
http://www.example.com/trip/tr/public/pl_ds?Id=454354×tamp=06280314546&bid=7667&source=ref
http://www.example.com/trip/tr/public/pl_ds?Id=454354%27';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php