private function getUpdateStatement($usePlaceholders = true)
    {
        $statement = "";

        if (!$this->isUpdate()) {
            return $statement;
        }

        $statement .= $this->getUpdateString();

        if ($this->isInto) {
            $statement .= " " . $this->getIntoString($usePlaceholders);
        } else {
            if ($this->set) {
                $statement .= " " . $this->getSetString($usePlaceholders);
            }
        }

        if ($this->where) {
            $statement .= " " . $this->getWhereString($usePlaceholders);
        }

        // ORDER BY and LIMIT are only applicable when updating a single table.
        if (!$this->join) {
            if ($this->orderBy) {
                $statement .= " " . $this->getOrderByString();
            }

            if ($this->limit) {
                $statement .= " " . $this->getLimitString();
            }
        }

        return $statement;
    }