$re = '/Aggregate\(.*\)(?=,)/';
$str = 'Substr(Aggregate(SubQuery, SUM, [Model].Remark * [Object].Shortname + 10), 0, 1)
Substr(Aggregate(SubQuery, SUM, [Model].Remark * ([Object].Shortname + 10)), 0, 1)
Substr(Aggregate(SubQuery, SUM, ([Model].Remark) * ([Object].Shortname + 10) ), 0, 1)';
preg_match_all($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