public function removeUnnamedPlaceHolder(int $placeholderIndex) : self
    {
        if ($this->usingUnnamedPlaceholders === false) {
            throw new InvalidQueryException('Cannot mix unnamed placeholders with named placeholders');
        }

        unset($this->parameters[$placeholderIndex]);
        // Re-index the array
        $this->parameters = array_values($this->parameters);

        return $this;
    }