PHP Warning: Division by zero?!

STEP 1:   

This warning can happen if a variable is not set then it is NULL and if you try to divide something by null you will get a divides by zero error. For example: 

This code will occur error: 

$get_likes = mysqli_query($conn1,"SELECT * FROM ratings WHERE videoid='$videoid' AND type='like'");
$num_of_likes = mysqli_num_rows($get_likes);

$get_dislikes = mysqli_query($conn1,"SELECT * FROM ratings WHERE videoid='$videoid' AND type='dislike'");
$num_of_dislikes = mysqli_num_rows($get_dislikes);

$total_num = $num_of_likes + $num_of_dislikes;

$width_of_one = $total_width / $total_num;

Now in this code, I've pointed out (red mark) the like for this line it will show division by zero error as it is trying to divide something by null. So, to remove this error what we can do is, we can simply put a @ sign before $num_of_likes + $num_of_dislikes.

Example: 

 $total_num = @($num_of_likes + $num_of_dislikes);

This one is simple right?! it will remove null and of course it will remove this error. 


STEP 2:
 Another way is, 
create an if statement before this:
$total_num = $num_of_likes + $num_of_dislikes;


Example:

$total_num_db = $num_of_likes + $num_of_dislikes;

if($total_num_db == 0){
 echo '  ';
} else{
        $total_num = $num_of_likes + $num_of_dislikes;
}




Here, $total_num_db means if the video has no likes or dislikes we will echo nothing/ do nothing or else run the code perfectly.