PHP & SQL Photo Gallery Placeholder Image - php

Question

I have a function called RandomPic() it will display a Random Photo from the Database. Now i want a Placeholder Image for the Gallerys Categories that are empty. but my code doesnt work. it doesn't show the placeholder image....any ideas? here is the code:
$sql = "SELECT * FROM wp_gallery WHERE catid = $id ORDER BY RAND() LIMIT 1";
if($result = $conn->query($sql)){
while ($row = mysqli_fetch_array($result))
{
if (mysqli_num_rows($result) > 0) {$imglos = '<img class="img-responsive" src="http://www.anyurl.com'.$row["filename"].'">';}
}
}
else{$imglos = 'PLACEHOLDERIMAGE GOES HERE';}
return $imglos;
}

Answer 1

Slightly change your code structure:
$sql = "SELECT * FROM wp_gallery WHERE catid = $id ORDER BY RAND() LIMIT 1";
if($result = $conn->query($sql))
{
if (mysqli_num_rows($result) > 0)
{
$row = mysqli_fetch_array($result))
$imglos = '<img class="img-responsive" src="http://www.anyurl.com'.$row["filename"].'">';
}
else
$imglos = 'TEST';
return $imglos;
}
else
return "database error!";
Some notes:
The mysqli_num_rows never changes after executing a query: it returns the number of rows in the resultset. So it makes no sense to check for this within a while.
There is no need for while, because your query can only return 0 or 1 results. If you do want to return multiple images you can append to $imglos:
while ( $row = mysqli_fetch_array($result) )
$imglos .= '<img class="img-responsive" src="http://www.anyurl.com'.$row["filename"].'">';