为什么没有从select查询中获取所有记录？

Question

代码：

 $sql = "SELECT stop_id FROM routes WHERE busNumber= '" . $busNumber."'";
        $result = $conn->query($sql);
        
        if ($result->num_rows > 0)
        {
            echo $result->num_rows."records fetched"."<br>";
            while($row = $result->fetch_assoc())
            {
                $stop_id = $row["stop_id"];
                //break;
                $sql = "SELECT stop_name FROM stops WHERE stop_id = '" . $stop_id."'";
                $result = $conn->query($sql);
                        
                if ($result->num_rows > 0)
                {
                    // output data of each row
                    while($row = $result->fetch_assoc())
                    {
                        $stop = $row["stop_name"];
                        echo "stop is->".$stop."<br>";
                        $result_stops .= $stop;
                        $result_stops .= ";";
                        //break;
                    }
                } 
            }
            echo "stops are". $result_stops. "<br>";
        }
       


echo "end". "<br>";

结果：

3 records fetched<br>stop is->PATIA<br>stops arePATIA;<br>end<br>

这里，从select查询中获取3条记录

但是，在while($row =$Result->fetch())中，循环没有运行，只有一个记录显示为PATIA，而不是3个记录。为什么其他人不露面？

Answer 1

@chinpin，这应该可以解决你的问题。正如我所评论的，您正在覆盖在外部“with”循环中使用的变量，得到不同的结果。

 $sql = "SELECT stop_id FROM routes WHERE busNumber= '" . $busNumber."'";
        $result = $conn->query($sql);
        
        if ($result->num_rows > 0)
        {
            echo $result->num_rows."records fetched"."<br>";
            while($row = $result->fetch_assoc())
            {
                $stop_id = $row["stop_id"];
                //break;
                $sql = "SELECT stop_name FROM stops WHERE stop_id = '" . $stop_id."'";
                $result2 = $conn->query($sql);
                        
                if ($result2->num_rows > 0)
                {
                    // output data of each row
                    while($row2 = $result2->fetch_assoc())
                    {
                        $stop = $row2["stop_name"];
                        echo "stop is->".$stop."<br>";
                        $result_stops .= $stop;
                        $result_stops .= ";";
                        //break;
                    }
                } 
            }
            echo "stops are". $result_stops. "<br>";
        }
       


echo "end". "<br>";