default image if file not exist mysql pdo - mysql

Question

I'm trying to add a default image in a query, if the file does not exist.
I succeeded when the query doesn't have a while loop. But since i need to loop this values. i would like to add the default image to the query.
I wont get any errors, its just printing out some random info from my DB.
function fetch_tweets($uid){
$uid = (int)$uid;
$query = $this->link->query
("SELECT user.id, user.email, user.username, tweets.message, tweets.date,
userdetails.profile_img, userdetails.firstname, userdetails.lastname,
following.id, following.user_id, following.follow_id
FROM user
LEFT JOIN
following ON user.id = following.user_id
JOIN userdetails ON user.id = userdetails.user_id
JOIN tweets ON userdetails.user_id = tweets.user_id
WHERE user.id='{$uid}'
OR
user.id IN (SELECT follow_id
FROM following
WHERE
following.user_id = '{$uid}' )
GROUP BY tweets.date ORDER BY tweets.date DESC "
);
$tweet = array();
while(($row = $query->fetch(PDO::FETCH_ASSOC)) !==FALSE) {
$tweet[] = $row;
$tweet['profile_img'] = (file_exists("img/{$uid}.jpg")) ?
"img/{$uid}.jpg" : "img/default.jpg" ;
}
return $tweet;
}

Answer 1

You're using the variable $tweet in the wrong way in your loop.
The following line will add a new element to the array $tweet:
$tweet[] = $row;
And the following line updates the element called "profile_img" in your $tweet array:
$tweet['profile_img'] = "...";
But I think, what you want is something like this:
while(($row = $query->fetch(PDO::FETCH_ASSOC)) !== FALSE) {
// Update the value for profile_img in the row
$row['profile_img'] = file_exists("img/{$uid}.jpg") ? "img/{$uid}.jpg" : "img/default.jpg" ;
// Add the manipulated row to the $tweet-array
$tweet[] = $row;
}
Please test using a debugger like xdebug (maybe a bit complicated to set up if you're not familiar with PHP) or just use var_dump();. You would've found that out pretty soon ...