$re = '/(?:\G(?!\A),|SELECT)(?:\s+[^\s,]+(?:\([^()]*\))?,)*\s*\K[^\s,]+\s*(?:(?![()\',])[[:punct:]]|AS)\s*(?:(?!FROM)[^,])*(?!\w)/m';
$str = 'SELECT col, col2 AS c2, col3, col * col2 calc FROM...
SELECT name, Concat(street, \' \', city, \', \', state, \' \', zipcode) AS address
SELECT name, Concat(street, \' \', city, \', \', state, \' \', zipcode), abc AS address';
preg_match_all($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