$re = '/{[^}]*"updated_at":"(?!2020-10-12)[^"]*"}/';
$str = '[{"id":"1","status":"0","created_at":"2020-10-12 12:00:00","updated_at":"2020-10-12 12:00:00"},{"id":"2","status":"1","created_at":"2020-10-13 12:00:00","updated_at":"2020-10-13 12:00:00"},
{"id":"3","status":"2","created_at":"2020-10-14 12:00:00","updated_at":"2020-10-14 12:00:00"}]';
preg_match_all($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