关注/取消关注工具PHP / mySQL

Question

I am sure I am missing something obvious or the mySQL code I have written for this tool is incorrect.

What I have got is a site that allow people to follow each other. If they are following a user they should see updates from them in their user dashboard.

I have had to tie several tables together in mySQL query to get the relevant information.

Here are the tables

users

ID                Username           Password
-------------|---------------|------------------
    1              User1         UserPass
    2              User2         UserPass
    3              User3         UserPass

user_details

ID                UserID           UserPhoto
-------------|---------------|------------------
    1              1            User1photo.jpg
    2              2            User2photo.jpg
    3              3            User3photo.jpg

userstatusposts

UserStatusID       UserID           status
-------------|---------------|------------------
    1              1            Hey My first post
    2              2            Woah this is cool
    3              3            It doesnt work

followers

followid       followerUserID   beingFollowedUserID
-------------|---------------|------------------
    1              3            1

There are more cols and rows in these tables but this is a basic form for the question.

As you can see from the followers table User3 is following User1 and should therefore be able to see the posts they have made in userstatusposts, the reason user details and users also need tying in is so I can display the users photo and the users username

The SQL I have at the moment that isn't working is:

SELECT * FROM userstatusposts 
                JOIN followers ON userstatusposts.userid = followers.followeruserid 
                JOIN users ON userstatusposts.userid = users.id 
                JOIN user_details ON userstatusposts.userid = user_details.userid 
                WHERE followers.beingFollowedUserID='$userid' 
                ORDER BY userstatusposts.userstatusid DESC
                LIMIT 10

However this is all tied together wrong as I see the posts of the wrong users when it is implemented in to my PHP code ($userid is the logged in user).

PHP Page:

 <?php
                $sql = "SELECT * FROM userstatusposts 
                JOIN followers ON userstatusposts.userid = followers.followeruserid 
                JOIN users ON userstatusposts.userid = users.id 
                JOIN user_details ON userstatusposts.userid = user_details.userid 
                WHERE followers.beingFollowedUserID='$userid' 
                ORDER BY userstatusposts.userstatusid DESC
                LIMIT 10
                ";

                $result = $conn->query($sql);
                $rowcount=mysqli_num_rows($result);
                if ($rowcount === 0) {
                  echo '<li style="list-style-type: none;"><p>Your not currently folllowing anyone.</p></li>';
                } else {
                  while($row = $result->fetch_assoc()) {
                    if ($row['posttype'] == 'message') {
                      echo '<li style="list-style-type: none;"><a href="#"><img src="userimg/'.$row['userphoto'].'" height="90px" width="90px"></a><h3><a href="#">'.$row['username'].'</a></h3><small>17/06/2014</small><p>'.$row['status'].'</p></li>';
                    }
                    else if ($row['posttype'] == 'map') {
                      echo '<li style="list-style-type: none;"><a href="#"><img src="userimg/'.$row['userphoto'].'" height="90px" width="90px"></a><h3><a href="#">'.$row['username'].'</a></h3><p>has recently added <b>'.$row['status'].'</b> to there travel map</p></li>';
                    }
                    else if ($row['posttype'] == 'like') {
                      echo '<li style="list-style-type: none;"><a href="#"><img src="userimg/'.$row['userphoto'].'" height="90px" width="90px"></a><h3><a href="#">'.$row['username'].'</a></h3><p>has recently liked a trip report called <b>'.$row['status'].'</b></p></li>';
                    }
                    else if ($row['posttype'] == 'report') {
                      echo '<li style="list-style-type: none;"><a href="#"><img src="userimg/'.$row['userphoto'].'" height="90px" width="90px"></a><h3><a href="#">'.$row['username'].'</a></h3><p>has recently shared a trip report called <b>'.$row['status'].'</b></p></li>';
                    }
                    else {
                      echo 'We are currently expirencing a few diffculties';
                    }
                  }

                }
              ?>

I am aware there are other cols being used here but they are in the tables listed above I have just left them out for the question.

Any suggestions why my SQL code is bringing back the wrong information, is it something glaringly obvious I have over looked?

Answer 1

Your query returns all the status of followers, not the status of followed.

You should change

WHERE followers.beingFollowedUserID='$userid' 

to

WHERE followers.followerUserID = '$userid' 

In addition, this is unrelated to your question, but your code has a security problem. You should sanitize $userid first before using it in your query.

$userid = (int)$userid

// .. now $userid is safe to use in $sql

Answer 2

The issue was one of the JOINS was looking to the wrong field.

The SQL should of been:

JOIN followers ON userstatusposts.userid = followers.beingFollowedUserID 

So the full statement is

SELECT * FROM userstatusposts 
                JOIN followers ON userstatusposts.userid = followers.beingFollowedUserID 
                JOIN users ON userstatusposts.userid = users.id 
                JOIN user_details ON userstatusposts.userid = user_details.userid 
                WHERE followers.followerUserID = '$userid'  
                ORDER BY userstatusposts.userstatusid DESC
                LIMIT 10

This was solved by a friend of mine not me, but thought I would share the answer for anyone interested.