public function setColumn($column, $operator = Condition::OPERATOR_OR)
    {
        $columnAlreadySet = count($this->column) > 0;
        if (!Condition::isOperator($operator) && $columnAlreadySet) {
            $msg = sprintf("Operator must be '%s' or '%s'.", Condition::OPERATOR_AND, Condition::OPERATOR_OR);
            throw new Exception($msg);
        }

        if ($columnAlreadySet) {
            $this->column[] = $operator;
            $this->column[] = $column;
        } else {
            $this->column[] = $column;
        }

        return $this;
    }