$re = '/(--.*)|(((\/\*)+?[\w\W]+?(\*\/)+))/';
$str = '--GO
--SET ANSI_NULLS ON
--GO
--SET QUOTED_IDENTIFIER ON
--GO
/*
DECLARE @Gas SMALLDATETIME = \'1/1/2016\',
@System VARCHAR(Max) = \'30\',--\'12,76,466,465,30,226\',
/*following param is to help decide Transportation or Storage */
@Contract INT = 0,--Transport or (1 = storage).
/*following param is to help decide dth or %*/
-- Contract Period 0 = 5 Years, 1 = 10 years,..., 4=25 years
*/';
preg_match_all($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