$re = '/(.*?)(?:\b(and|or|not)\b|$)/';
$str = 'some column name1 = some value1 and some column name2 < another value2 or some column name 3 > value3 not column name 4 = value4 and name5 = value5';
preg_match_all($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