Let's Play Spot The Error

    function save() {
        global $db;

        ob_start();
        
        $args = array();

        print 'UPDATE tbl_property';
        print ' SET ';

        if ($this->getAddress() !== null) {
            $param[] = "add_id = ?";
            $args[] = $this->getAddress();
        }

        if ($this->getZoneEffect() !== null) {
            $param[] = "ppt_zone_effect = ?";
            $args[] = $this->getZoneEffect();
        }

        if ($this->getZone() !== null) {
            $param[] = "ppt_zone = ?";
            $args[] = $this->getZone();
        }

        if ($this->getParent() !== null) {
            $param[] = "ppt_parent_id = ?";
            $args[] = $this->getParent();
        }

        if ($this->getLGA() !== null) {
            $param[] = "lga_id = ?";
            $args[] = $this->getLGA();
        }

        if ($this->getPT() !== null) { 
            $param[] = "pt_id = ?";
            $args[] = $this->getPT();
        }

        if ($this->getAreaType() !== null) {
            $param[] = "areatype_id = ?";
            $args[] = $this->getAreaType();
        }

        if ($this->getArea() !== null) {
            $param[] = "ppt_area = ?";
            $args[] = $this->getArea();
        }

        if ($this->getCTFolio() !== null) {
            $param[] = "ppt_ct_folio = ?";
            $args[] = $this->getCTFolio();
        }
        
        if ($this->getCTVolume() !== null) {
            $param[] = "ppt_ct_volume = ?";
            $args[] = $this->getCTVolume();
        }
        
        if ($this->getLotNumber() !== null) {
            $param[] = "ppt_lot_no = ?";
            $args[] = $this->getLotNumber();
        }
        
        if ($this->getLocation() !== null) {
            $param[] = "ppt_location = ?";
            $args[] = $this->getLocation();
        }
        
        if ($this->getDimensions() !== null) {
            $param[] = "ppt_dimensions = ?";
            $args[] = $this->getDimensions();
        }
        
        if ($this->getIdentifiedBy() !== null) {
            $param[] = "ppt_identified_by = ?";
            $args[] = $this->getIdentifiedBy();
        }
        
        if ($this->getDepositedPlanNumber() !== null) {
            $param[] = "ppt_deposited_plan_no = ?";
            $args[] = $this->getDepositedPlanNumber();
        }
        
        if ($this->getNeighbourhoodDescription() !== null) {
            $param[] = "ppt_neighbourhood_description = ?";
            $args[] = $this->getNeighbourhoodDescription();
        }
        
        if ($this->getZoneInstrument() !== null) 
            $param[] = "ppt_zone_instrument = ?";
            $args[] = $this->getZoneInstrument();
        

        if ($this->getSiteDescription() !== null) {
            $param[] = "ppt_site_description = ?";
            $args[] = $this->getSiteDescription();
        }
        
        
        //glue together array pieces.
        print implode(', ',@$param);

        print ' WHERE ppt_id = ?';
        $args[] = $this->getID();

        $query = ob_get_clean();

        if (count(@$param) > 0) {
            $db->query($query, $args);
        }

        return true;
    }

It's producing:
$args[0] = int
$args[1] = null
$args[2] = int

when it should produce:
$args[0] = int
$args[1] = int

Time wasted by me before spotting this error:
27 minutes.

Foolishness level:
High

Lesson learned:
Don't be stupid and use a different font in your text editor.