MySQL and PHP - insert NULL rather than empty string

Question

I have a MySQL statement that inserts some variables into the database. I recently added 2 fields which are optional ($intLat, $intLng). Right now, if these values are not entered I pass along an empty string as a value. How do I pass an explicit NULL value to MySQL (if empty)?

$query = "INSERT INTO data (notes, id, filesUploaded, lat, lng, intLat, intLng)
          VALUES ('$notes', '$id', TRIM('$imageUploaded'), '$lat', '$long', 
                  '$intLat', '$intLng')";
mysql_query($query);

Answer 1

If your variable already contains null, prepared statements will do it for you without any extra code

$query = "INSERT INTO data (notes, id, filesUploaded, lat, lng, intLat, intLng)
          VALUES (?,?,?,?,?,?)";
$data = [$notes, $id, $imageUploaded, $lat, $long, $intLat, $intLng];
$conn->prepare($query)->execute($data);

as simple as that.

Any variable that contains a PHP null will be written as MySQL null. Not to mention this query is safe from SQL injection.

If case you want to set a variable to null if it contains an empty string, here is how you can do it before running this query:

$intLat = ($intLat === '') ? null : $intLat;