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Question

Im trying to find an efficient way to display all posts from people who are being followed by the logged in account holder.

There are two key tables:

1- Posts

table name : posts

id , account_name , published, body

2- Follows

Table name : follows

id , account_name , followed_name

I'm trying to find a way that i can display all the posts from all the accounts that are being followed. The connection between Posts and Follows is the Account_name .

I understand that it will probably be a join, but it's how I construct the WHERE clause. So far I have the following (The account name is set via $_SESSION['account_name']):

$sql = "SELECT * FROM posts LEFT JOIN follows ON posts.account_name = follows.account_name WHERE  --- How would I only get the posts from the accounts being followed ?---"

I'm sure this is something simple my brain just feels drained and I cant seem to work it out.

UPDATE Attempting in PDO

Returning NULL at the moment,

$sql = "SELECT * FROM share_posts WHERE account_name IN (SELECT followed_name FROM $this->account_follows WHERE account_name = :account_name)";
    return $this->AC->Database->select($sql, array('account_name' => $account_name)); 

The goes to my Database Class:

    public function select($sql, $array = array(), $fetch_mode = PDO::FETCH_ASSOC)
    {

        $stmt = $this->AC->PDO->prepare($sql);

        foreach ($array as $key => $value) 
        {
            $stmt->bindValue("$key", $value);
        }

        $stmt->execute();

        return $stmt->fetchALL($fetch_mode);

    }

The returned data is NULL at the moment even though the logged in account has followed other accounts.

Answer 1

$account = $_SESSION['account_name'];

//do some sql injection checking on $account here

$sql = "SELECT * FROM posts WHERE account_name IN (SELECT followed_name FROM follows WHERE account_name='".$account."')";

This will get all the posts where the account name matches somebody you follow. I wasnt sure who was following who, but in this case the followed_name are the people account_name is following. If thats the other way around, switch the values

$sql = "SELECT * FROM posts WHERE account_name IN (SELECT account_name FROM follows WHERE followed_name='".$account."')";

Answer 2

I will write this the way I interpret your question.

What you need to do is select only the posts from the users that are followed by your logged in user.

To break this down, first you want to select the users followed by the logged in user. To do this, we use the Follows table.

We then want to select the posts by these users. As such my query would be this.

SELECT posts.* FROM follows
    LEFT JOIN posts ON posts.account_name = follows.follows_name
    WHERE follows.account_name = $logged_in_user