php - 如果条件不起作用则嵌套

Question

我在我的项目中嵌套了 if 条件，但我遇到了问题；

if(isset($_GET['q']) && isset($_GET['t'])) {
  $query = $_GET['q'];
  $type = $_GET['t'];
  $none_key = FALSE;

  if($type = 'singer') {
      $singers = $connect->query("SELECT * FROM lyrica_singers WHERE singer_name LIKE '%$query%'");
      $control = $singers->rowCount();

      if($control > 0)  {
        $on_page = 24;
        $number_singers = $singers->rowCount();
        $number_page = ceil($number_singers/$on_page);

        $page = isset($_GET['p']) ? (int) $_GET['p'] : 1;
        if ($page < 1) $page = 1;
        if ($page>$number_page) $page = $number_page;

        $limit = ($page - 1) * $on_page;

        $singers = $connect->query("SELECT * FROM lyrica_singers WHERE singer_name LIKE '%$query%' ORDER BY singer_name ASC LIMIT ".$limit.",".$on_page);
        $singer_key = TRUE;
      } else {
        $none_key = TRUE;
      }
    }

    if($type = 'song') {
      $songs = $connect->query("SELECT * FROM lyrica_songs WHERE song_name LIKE '%$query%'");
      $control = $songs->rowCount();

      if($control > 0)  {
        $on_page = 24;
        $number_songs = $songs->rowCount();
        $number_page = ceil($number_songs/$on_page);

        $page = isset($_GET['p']) ? (int) $_GET['p'] : 1;
        if ($page < 1) $page = 1;
        if ($page>$number_page) $page = $number_page;

        $limit = ($page - 1) * $on_page;

        $songs = $connect->query("SELECT * FROM lyrica_songs WHERE song_name LIKE '%$query%' ORDER BY song_name ASC LIMIT ".$limit.",".$on_page);
        $song_key = TRUE;
      } else {
        $none_key = TRUE;
      }
    }
} else {
  $key = TRUE;
}

当我运行代码时，我期望如果“control”变量之一大于 0，则“none_key”变量必须等于 0。当“type”变量为“song”时，没有问题但是如果'type'变量是'singer'然后'none_key'变量打印1，我认为它正在运行第二个if block 并变为'none_key'1因为第二个'control'变量不大于零。

Answer 1

这是一个赋值，它将$type设置为值singer:

if ($type = 'singer') {

你想要一个比较，它会检查 $type 是否等于 singer 的值:

if ($type == 'singer') {

[编辑] 有些人喜欢用最后一个变量来编写这种语句。这通常称为“尤达条件”:

if ('singer' == $type) {

这样一来，如果你搞砸了并且只使用了一个 =，你会得到一个错误。