选择按xxx desc的最高喜欢/不喜欢顺序评论的帖子

Question

我有两个表， posts和comments 。 posts表的列为： id, body, user_id, likes, dislikes, time 。 comments表id, body, post_id, user_id, likes, dislikes, time ： id, body, post_id, user_id, likes, dislikes, time 。

让我们假设一个场景有两个帖子（A和B）。 帖子A具有1个评论，具有10个赞和2个赞，帖子B具有1条评论，具有5个赞和12个赞。

通过API端点category对帖子进行排序时，如果请求请求的是most disliked评论，那么我如何实现ORDER BY comment.likes/dislikes DESC以Post-B开头的ORDER BY comment.likes/dislikes DESC语句。 如果请求是most liked评论，则从Post-A开始。

这就是我当前的查询（按任何评论请求的发帖数量排序）的样子。 请注意，我不是从comments表中选择，因为在提取帖子后，将为每个帖子ID加载评论。

<?

if (isset($_GET['ordertags'])) {
  //post tags e.g general/work/school etc
  $orderTags = $_GET['ordertags'];
}else {
  $orderTags = "alltags";
}

if (isset($_GET['orderreactions'])) {
  //post reactions, e.g date time/ most post-likes/dislikes/comments & comment-likes/dislikes etc
  $orderReactions = $_GET['orderreactions'];
}else {
  $orderReactions = "pdt";
}

//declare vars
$orderBy = "";
//get start offset to load the first 10 results
$start = (int)$_GET['start'];

switch ($orderReactions) {
  case "pdt":
    $orderBy = "ORDER BY posts.posted_at";
    break;
  case "mlp":
    $orderBy = "AND posts.likes != 0 ORDER BY posts.likes";
    break;
  case "mdp":
    $orderBy = "AND posts.dislikes != 0 ORDER BY posts.dislikes";
    break;
  case "mcp":
    $orderBy = "AND posts.comments != 0 ORDER BY posts.comments";
    break;
  case "mlc":
    $orderBy = "AND posts.comments != 0 ORDER BY posts.comments";
    break;
  case "mdc":
    $orderBy = "AND posts.comments != 0 ORDER BY posts.comments";
    break;
  default:
    $orderBy = "ORDER BY posts.posted_at";
    break;
}

//posts from users 
if ($orderTags == "alltags") {

  $followingposts = $db->query('SELECT posts.id, posts.body, posts.posted_at, posts.likes, posts.dislikes, posts.tags, users.`username`, users.`profileimg` FROM users, posts
    WHERE users.id = posts.user_id
    '.$orderBy.' DESC LIMIT 10 OFFSET '.$start.';');

}else {

  $followingposts = $db->query('SELECT posts.id, posts.body, posts.posted_at, posts.likes, posts.dislikes, posts.tags, users.`username`, users.`profileimg` FROM users, posts
    WHERE users.id = posts.user_id
    AND tags = :tag
    '.$orderBy.' DESC LIMIT 10 OFFSET '.$start.';', array(':tag'=>$orderTags));

}


?>

这就是我的comments终结点，它看起来像没有问题一样，它可以检索最喜欢/不喜欢的注释。

<?

if (isset($_GET['action'])) {
  //comment action request i.e most liked/disliked/regular i.e postDate
  $action = $_GET['action'];
}else {
  $action = "reg";
}

//declare vars
$orderBy = "";

switch ($action) {
    case "mdc":
        $orderBy = "ORDER BY comments.dislikes DESC";
        break;
    case "mlc":
        $orderBy = "ORDER BY comments.likes DESC";
        break;
    case "reg":
        $orderBy = "ORDER BY comments.posted_at ASC";
        break;
    default:
        $orderBy = "ORDER BY comments.posted_at ASC";
        break;
}

//fetch comments from db
$comments = $db->query('SELECT comments.id, comments.comment, comments.post_id, comments.posted_at, comments.likes, comments.dislikes, users.username, users.profileimg FROM comments, users WHERE comments.post_id = :postid AND comments.user_id = users.id '.$orderBy.';', array(':postid'=>$_GET['postid']));   


?>

因此，问题在于如何在ORDER BY DESC语句中选择具有最高喜欢/不喜欢评论的帖子，同时仍排除具有0个喜欢/不喜欢评论的帖子。 谢谢。

Answer 1

您可以使用JOINS排除评论为0赞/不喜欢的帖子（选择帖子。* FROM帖子JOIN在ON.Posts.id = Comments.post_id上添加评论，在Comments.likes> 0 AND Comments.dislikes> 0上）

Answer 2

添加了一个INNER JOIN一切正常

 <? switch ($orderReactions) { case "pdt": if ($orderTags == "alltags") { $orderBy = "WHERE users.id = posts.user_id ORDER BY posts.posted_at"; }else { $orderBy = "WHERE users.id = posts.user_id AND tags=:tag ORDER BY posts.posted_at"; } break; case "mlp": if ($orderTags == "alltags") { $orderBy = "WHERE users.id = posts.user_id AND posts.likes != 0 ORDER BY posts.likes"; }else { $orderBy = "WHERE users.id = posts.user_id AND tags=:tag AND posts.likes != 0 ORDER BY posts.likes"; } break; case "mdp": if ($orderTags == "alltags") { $orderBy = "WHERE users.id = posts.user_id AND posts.dislikes != 0 ORDER BY posts.dislikes"; }else { $orderBy = "WHERE users.id = posts.user_id AND tags=:tag AND posts.dislikes != 0 ORDER BY posts.dislikes"; } break; case "mcp": if ($orderTags == "alltags") { $orderBy = "WHERE users.id = posts.user_id AND posts.comments != 0 ORDER BY posts.comments"; }else { $orderBy = "WHERE users.id = posts.user_id AND tags=:tag AND posts.comments != 0 ORDER BY posts.comments"; } break; case "mlc": if ($orderTags == "alltags") { $orderBy = "INNER JOIN comments ON comments.post_id = posts.id WHERE posts.user_id = users.id AND posts.comments != 0 AND comments.likes != 0 GROUP BY post_id ORDER BY comments.likes"; }else { $orderBy = "INNER JOIN comments ON comments.post_id = posts.id WHERE posts.user_id = users.id AND tags=:tag AND posts.comments != 0 AND comments.likes != 0 GROUP BY post_id ORDER BY comments.likes"; } break; case "mdc": if ($orderTags == "alltags") { $orderBy = "INNER JOIN comments ON comments.post_id = posts.id WHERE posts.user_id = users.id AND posts.comments != 0 AND comments.dislikes != 0 GROUP BY post_id ORDER BY comments.dislikes"; }else { $orderBy = "INNER JOIN comments ON comments.post_id = posts.id WHERE posts.user_id = users.id AND tags=:tag AND posts.comments != 0 AND comments.dislikes != 0 GROUP BY post_id ORDER BY comments.dislikes"; } break; default: if ($orderTags == "alltags") { $orderBy = "WHERE users.id = posts.user_id ORDER BY posts.posted_at"; }else { $orderBy = "WHERE users.id = posts.user_id AND tags=:tag ORDER BY posts.posted_at"; } break; } //posts from users followed by current logged in user + logged in user if ($orderTags == "alltags") { $followingposts = $db->query('SELECT posts.id, posts.body, posts.posted_at, posts.likes, posts.dislikes, posts.tags, posts.user_id, users.`username`, users.`profileimg` FROM users, posts '.$orderBy.' DESC LIMIT 10 OFFSET '.$start.';'); }else { $followingposts = $db->query('SELECT posts.id, posts.body, posts.posted_at, posts.likes, posts.dislikes, posts.tags, posts.user_id, users.`username`, users.`profileimg` FROM users, posts '.$orderBy.' DESC LIMIT 10 OFFSET '.$start.';', array(':tag'=>$orderTags)); } ?>