How to combine multiple if conditions

How to combine multiple if conditions
Title: Code efficiency is not high, redundancy is too much, online and so on.

PHP Code

  if ($start _id = = $first _id && $arrive _id = = ") {echo" I am the first city City ";                    To inquire whether the first city has added transport $start _id = ';                    $arrive _id = $first _id;                    $res = $this->model->get_traffic ($tripid, $type, $start _id, $arrive _id);  if ($res) {$affected _rows = $this->model->update_traffic ($traffic, $tripid, $type, $start _id,                        $arrive _id); if ($affected _rows > 0) {echo "updated successfully!                        "; }}else{$trafficid = $this->model->add_traffic ($traffic, $tripid, $start _                        ID, $arrive _id, $type, $dateline);                        if ($trafficid > 0) {echo ' Add success ';                }} exit;                   if ($start _id = = $last _id && $arrive _id = = ") { echo "I am the last city";                    $start _id = $last _id;                    $arrive _id = ";                                        $res = $this->model->get_traffic ($tripid, $type, $start _id, $arrive _id);  if ($res) {$affected _rows = $this->model->update_traffic ($traffic, $tripid, $type, $start _id,                        $arrive _id); if ($affected _rows > 0) {echo "updated successfully!                        "; }}else{$trafficid = $this->model->add_traffic ($traffic, $tripid, $start _                        ID, $arrive _id, $type, $dateline);                        if ($trafficid > 0) {echo ' Add success ';                }} exit;                if ($start _id = = ' && $arrive _id = = ') {echo "Requires 2 cities to add transportation";                    }else{echo "Select right can be put into storage";$res = $this->model->get_traffic ($tripid, $type, $start _id, $arrive _id);  if ($res) {$affected _rows = $this->model->update_traffic ($traffic, $tripid, $type, $start _id,                        $arrive _id); if ($affected _rows > 0) {echo "updated successfully!                        "; }}else{$trafficid = $this->model->add_traffic ($traffic, $tripid, $start _                        ID, $arrive _id, $type, $dateline);                        if ($trafficid > 0) {echo ' Add success ';            }}}} $this->display = true;            $this->view->assign (' cities ', $cities);            $this->view->assign (' Traffic ', $_config[' traffic ');            $this->view->assign (' Tripid ', $tripid);            $this->view->assign (' Cityid ', $cityid); $this->view->assIGN (' type ', $type);        }else if ($type = = 2) {echo "I'm here to add the sights of gourmet green"; }

------Solution--------------------
Does your if else {} bracket match? Why do I feel wrong?
------Solution--------------------
You can try it with switch!
------Solution--------------------
$res = $this->model->get_traffic ($tripid, $type, $start _id, $arrive _id);
if ($res) {
$affected _rows = $this->model->update_traffic ($traffic, $tripid, $type, $start _id, $arrive _id);
if ($affected _rows > 0) {
echo "Updated successfully! ";

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