Question

需要帮助才能完成此嵌套WHILE循环。

情景是

这是我的数据库中的5个表

user_info(userid,name,picurl)
user_friends(userid,friend_id)
user_post(userid,post_id,post,time)
user_likes(userid,post_id)
user_comments(userid,post_id)

我想访问user_post表并填充我的android应用程序中的数据。我可以从user_post表访问userid，post_id和time，并使用friend表中的用户的friend_id。现在要显示带有图片和名称的完整帖子，我需要访问发布者的姓名和图片来自user_info表。如果我需要显示一个1个朋友的帖子我可以做到这一点，但是当有几个朋友有超过1个帖子时，我无法得到用户的名字和picurl，并且它在json响应中显示为null。我使用Nested While循环进行此操作以下是我的代码。

$userid = $_POST['userid'];

$query = "SELECT * FROM user_friend WHERE userid = '$userid'";
$result = mysql_query($query);

$return_arr = array();
$return_arr['newsfeed'] = array();

//Access userid
while($row = mysql_fetch_assoc($result))    {

echo "Friend Name is ".$row['friend_id']. "<br>";       

$friend_id = $row['friend_id'];
$friend_id = mysql_real_escape_string($friend_id);

//accessing user_info table to access user info
$picquery = "SELECT * FROM user_info WHERE userid = '$friend_id'";
$picresult = mysql_query($picquery);

$pic = mysql_fetch_assoc($picresult);

$row_array['name'] = $pic['name'];
$row_array['picurl'] = $pic['picurl'];

$query2 = "SELECT * FROM user_post WHERE userid = '$friend_id'";
$result2 = mysql_query($query2);

//Access Posts Against userids
    while( $row = mysql_fetch_array($result2) ) {

                $post_id = $row['post_id'];

                //for number of likes
                $likesQuery = "SELECT COUNT(*) as totallikes FROM post_likes        WHERE post_id = '$post_id'";
                $likesResult = mysql_query($likesQuery);
                $likesvalues = mysql_fetch_assoc($likesResult); 
                $num_of_likes = $likesvalues['totallikes']; 

                //for number of comments
                $commentsQuery = "SELECT COUNT(*) as totalcomments FROM post_comments WHERE post_id = '$post_id'";
                $commentsResult = mysql_query($commentsQuery);
                $commentsvalues = mysql_fetch_assoc($commentsResult); 
                $num_of_comments = $commentsvalues['totalcomments'];

        $row_array['post_id'] = $row['post_id'];
        $row_array['userid'] = $row['userid'];
        $row_array['post_text'] = $row['post_text'];
        $row_array['post_time'] = $row['post_time'];
        $row_array['post_num_likes'] = $num_of_likes;
        $row_array['post_num_comments'] = $num_of_comments;

        array_push($return_arr['newsfeed'],$row_array);

    }
}
date_default_timezone_set('Asia/Karachi');
$date = date(' h:i:s a d/m/Y', time());         
echo json_encode($return_arr,JSON_UNESCAPED_SLASHES);

Answer 1

这样的事情可能会有所帮助。由于我没有任何测试数据，我无法看到它是如何工作的。它应该显示post_id以及喜欢的次数和评论

SELECT
  p.post_id,
  COUNT(c.post_id) AS comments_count,
  COUNT(l.post_id) AS like_count
FROM user_post p,
     user_likes l,
     user_comments c
WHERE p.post_id = l.post_id
AND p.post_id = c.post
GROUP BY p.post_id

PHP MYSQL嵌套While循环跳过迭代

1 个答案: