php - MySQL 连接查询似乎有效，但未按预期执行

Question

我对在 MySQL 中使用联接还比较陌生。

我有两个表:

sh_subscriptions
    => id
    => user_id
    => feed_id

sh_feeds
    => id
    => shop_name
    => feed_id

我正在尝试从 sh_subscriptions 获取所有字段，其中 feed_id 对应于 sh_feed 中的 feed_id对应于 $row['shop_name']，其中 user_id 对应于 $id['id]。

这是我的尝试:

SELECT * FROM sh_subscriptions s
INNER JOIN sh_feeds f ON s.shop_id = f.feed_id
WHERE s.id = '" . $id['id'] . "'
AND f.shop_name = '" . $row['shop_name'] . "'

更新

我现在有以下内容:

while($row = mysqli_fetch_array($query))
{
    echo "<div class='col-md-4'>";
    echo $row['shop_name'] . " ";
    $query = mysqli_query($con, "SELECT * FROM sh_subscriptions s INNER JOIN sh_feeds f ON s.feed_id = f.feed_id WHERE s.user_id = '" . $id['id'] . "' AND f.shop_name = '" . $row['shop_name'] . "'") or die(mysql_error($con));
    echo "</div>";
}

我可以确认数据库字段全部存在，并且变量打印正确，但尽管包含了错误处理程序，但 div 内没有任何内容被打印。

Answer 1

试试这个:

SELECT * FROM sh_subscriptions s
INNER JOIN sh_feeds f ON s.id = f.feed_id
WHERE s.id = '" . $id['id'] . "'
AND f.shop_name = '" . $row['shop_name'] . "'") or die(mysql_error($con));