Question

用户有订阅。它们存储在PHP数组中。我试图让所有属于按ID排序的订阅的帖子显示在新闻Feed中。我试图让所有这些循环抛出数组，然后按ID排序。我想知道是否有更简单的方法，因为我决定使用＆＃39; LIMIT＆＃39;只获得特定数量的帖子。

现在的问题是，我获得了所有帖子，而我只需要10个（例如）。我正在使用PDO，MySQL，PHP。这是我现在的代码：

foreach(subscriptions_arr as $sub) {
    $select = $db->prepare("select * from posts where owner_id = :owner_id");
    $select->bindParam(':owner_id', $sub);
    $select->execute();
    $posts = $select->fetchAll(PDO::FETCH_ASSOC);

    // pushes all of the posts into one multi-array with only 2 levels
    // (instead of 3 as before)
    // to be able to sort it by id, and not by subscriptions
    foreach ($posts as $post) {
        $new_array[] = $post;
    }
}
// sorts by id
usort($new_arr, function($a, $b) {
    return $b['id'] - $a['id'];
});

现在，如果我将限制为10，我将为每个订阅获得10个帖子，但我需要10个摘要（最新的（按ID排序））。

Answer 1

$select = $db->prepare("select * from posts where owner_id = :owner_id order by id");

这样，记录将按升序排序，阅读ORDER BY子句。

Answer 2

foreach(subscriptions_arr as $sub) {
$select = $db->prepare("select * from posts order by ID DESC group by owner_id LIMIT 10");
$select->execute();
$posts = $select->fetchAll(PDO::FETCH_ASSOC);

// pushes all of the posts into one multi-array with only 2 levels
// (instead of 3 as before)
// to be able to sort it by id, and not by subscriptions
foreach ($posts as $post) {
    $new_array[] = $post;
}
}
// sorts by id
usort($new_arr, function($a, $b) {
return $b['id'] - $a['id'];
});

Answer 3

如果您有一系列订阅，我建议您使用IN clausole。

\\

如何执行MySQL查询以获取按ID排序的不同订阅的所有行？

3 个答案: