PHP Mysql select 只显示一行

Question

我目前正在尝试制作电视剧的一页。不知何故，页面只显示一行 seasons，在我的数据库中是 5。

$sql = "SELECT * FROM `shows` WHERE url='".dburl($_GET["url"])."'";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
    while($row = $result->fetch_assoc()) {

    // General info about the TV show here

        $sql = "SELECT * FROM seasons WHERE `show`='".$row["id"]."' ORDER BY number ASC";
        $result = $conn->query($sql);

        if ($result->num_rows > 0) {
            while($seasons = $result->fetch_assoc()) {

            // The seasons

                $sql= "SELECT * FROM episodes WHERE `show`='".$row["id"]."' AND `season`='".$seasons["number"]."' ORDER BY number DESC";
                $result = $conn->query($sql);

                if ($result->num_rows > 0) {
                    while($episodes = $result->fetch_assoc()) {

                        // The episodes, sorted by season

                    }
                }

            }
        }

    }
}

有没有什么变化是我忽略了什么？ episodes 部分工作得很好，它显示了一个季节中的所有剧集。

Answer 1

我建议你在一个 mysql 查询中获取所有数据，使用适当的变量转义，这样代码会比你得到的代码更简单、更易读。那么也许您会犯更少的错误，但编码会更好:

$mysqli = new mysqli("localhost", "my_user", "my_password", "my_db");

/* check connection */
if (mysqli_connect_errno()) {
    printf("Connect failed: %s\n", mysqli_connect_error());
    exit();
}

  $sql = "SELECT * FROM `shows` sh
         JOIN `seasons` se.show ON sh.id
         JOIN `episodes` e ON e.show = se.id AND e.season = e.number
         WHERE url=?
         ORDER BY se.number, e.number";

  /* Prepare statement */
  $stmt = $conn->prepare($sql);
  if($stmt === false) {
    trigger_error('Wrong SQL: ' . $sql . ' Error: ' . $conn->errno . ' ' .$conn->error, E_USER_ERROR);
  }

   /* Bind parameters. Types: s = string, i = integer, d = double,  b = blob */
   $stmt->bind_param('s', dburl($_GET["url"]));

  /* Execute statement */
  $stmt->execute();

  /* Fetch result to array */
  $res = $stmt->get_result();
  while($row = $res->fetch_array(MYSQLI_ASSOC)) {
     array_push($a_data, $row);
  }

  /* close statement */
  $stmt->close();
}

/* close connection */
$mysqli->close();

理由或解释:

Never concatenate or interpolate data in SQL

Never build up a string of SQL that includes user data, either by concatenation:

$sql = "SELECT * FROM users WHERE username = '" . $username . "';";

or interpolation, which is essentially the same:

$sql = "SELECT * FROM users WHERE username = '$username';";

If '$username' has come from an untrusted source (and you must assume it has, since you cannot easily see that in source code), it could contain characters such as ' that will allow an attacker to execute very different queries than the one intended, including deleting your entire database etc. Using prepared statements and bound parameters is a much better solution. PHP's mysqli and PDO functionality includes this feature (see below).

来自 OWASP:PHP Security Sheet