protected function _splitFieldname($field) {
		$regex = '/^([a-z0-9_-]+)\.([a-z 0-9_-]+|\*)$/iS';

		if (strpos($field, '.') !== false && preg_match($regex, $field, $matches)) {
			return [$matches[1], $matches[2]];
		}
		return [null, $field];
	}
protected function _splitFieldname($field) {
		$regex = '/^([a-z0-9_-]+)\.([a-z 0-9_-]+|\*)$/iS';

		if (strpos($field, '.') !== false && preg_match($regex, $field, $matches)) {
			return [$matches[1], $matches[2]];
		}
		return [null, $field];
	}
protected function _splitFieldname ( $ field ) { $ regex = '/^([a-z0-9_-]+)\.([a-z 0-9_-]+|\*)$/iS' ; if ( strpos ( $ field , '.' ) !== false && preg_match ( $ regex , $ field , $ matches ) ) { return [ $ matches [ 1 ] , $ matches [ 2 ] ] ; } return [ null , $ field ] ; }
Return the alias and the field name from an identifier name.

@param string $field Field name or identifier name.
@return array Returns an array with the alias (or `null` if not applicable) as first value
and the field name as second value.
Return the alias and the field name from an identifier name .