function in($columnName, $values) {
		$sql = " ($columnName IN (";
		reset($values);
		$multi = false;
		foreach ($values as $key => $value) {
			if ($multi) $sql .= ', ';
			else $multi = true;
			$sql .= $this->convertConditionArgumentToSql($value);
		}
		$sql .= '))';

		$this->query .= $sql;
		return $sql;
	}