PHP脚本不返回第一个数组

Question

this PHP script is supposed to return the top five losers, the top five gainers and the five most active stocks in the form of arrays called result. when i run the query in the database it returns the right values but when i run the PHP script in the browser it doesn't return the first array, it starts from the second array ,the second array and so on. this is the script:

    switch ($which){
        case 'top':
            $sql = "SELECT * FROM market_table ORDER BY price_change DESC LIMIT 5";
            $result = $this -> connection->query($sql);
            if($result->num_rows > 0){
                $r = mysqli_query($this->connection,$sql);
                $res = mysqli_fetch_array($r);
                $result = array(); 
                while($res = mysqli_fetch_array($r)){
                    array_push($result,array("sympol"=>$res['sympol'],"o_price"=>$res['o_price'],
                    'e_name'=>$res['e_name'], 'price_change'=>$res['price_change'],'perc_change'=>$res['perc_change'],
                    'c_price'=>$res['c_price'],'volume'=>$res['volume'],'h_price'=>$res['h_price'],
                    'l_price'=>$res['l_price'],'deals_n'=>$res['deals_n'],
                    'value'=>$res['value']));
                }
                echo json_encode(array("result"=>$result));
            }           
            else{
                echo "top five: 0 results";
            }
        break;
        case 'bottom':
            $sql = "SELECT * FROM market_table ORDER BY price_change ASC LIMIT 5";
            $result = $this -> connection->query($sql);
            if($result->num_rows > 0){
                $r = mysqli_query($this->connection,$sql);
                $res = mysqli_fetch_array($r);
                $result = array(); 
                while($res = mysqli_fetch_array($r)){
                    array_push($result,array("sympol"=>$res['sympol'],"o_price"=>$res['o_price'],
                    'e_name'=>$res['e_name'], 'price_change'=>$res['price_change'],'perc_change'=>$res['perc_change'],
                    'c_price'=>$res['c_price'],'volume'=>$res['volume'],'h_price'=>$res['h_price'],'l_price'=>$res['l_price'],
                    'deals_n'=>$res['deals_n'],
                    'value'=>$res['value']));
                }
                echo json_encode(array("result"=>$result));
            }           
            else{
                echo "bottom five: 0 results";
            }
        break;
        case'most':
            $sql = "SELECT * FROM market_table ORDER BY deals_n DESC LIMIT 5";
            $result = $this -> connection->query($sql);
            if($result->num_rows > 0){
                $r = mysqli_query($this->connection,$sql);
                $res = mysqli_fetch_array($r);

                $result = array(); 
                while($res = mysqli_fetch_array($r)){
                    array_push($result,array("sympol"=>$res['sympol'],"o_price"=>$res['o_price'],
                    'e_name'=>$res['e_name'], 'price_change'=>$res['price_change'],'perc_change'=>$res['perc_change'],
                    'c_price'=>$res['c_price'],'volume'=>$res['volume'],'h_price'=>$res['h_price'],'l_price'=>$res['l_price'],
                    'deals_n'=>$res['deals_n'],
                    'value'=>$res['value']));
                }
                echo json_encode(array("result"=>$result));
            }           
            else{
                echo "most active five: 0 results";
            }
        break;
    }

Answer 1

$res = mysqli_fetch_array($r);
$result = array();

Why do you have those? You're not saving the result($res) since you're initializing the result($result) to an empty array on the 2nd line. So that's where your first line disappears.