用户有订阅。它们存储在PHP数组中。我正试图让所有属于id订购的订阅的帖子显示在新闻提要中。我试图让所有这些循环抛出数组,然后按ID对它们进行排序。我想知道是否有更简单的方法,因为我决定使用"LIMIT"只获取特定数量的帖子。
问题是,现在,我得到了所有的职位,而我只需要10个(例如)。我使用的是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个,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))。
如果您有一组订阅,我可以建议您使用IN子句。
$select = $db->prepare("select * from posts where owner_id IN(" .
implode(',',subscriptions_arr).") ORDER BY owner_id";
$result = $select->execute();
$select = $db->prepare("select * from posts where owner_id = :owner_id order by id");
这样记录将按升序排序,请阅读ORDERBY子句。
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'];
});