Come faccio ad inserire un valore null, io sto facendo cosi :
codice:
if(isset($_POST['text4'])&&($_POST['text4']=="")){
$text4 = NULL;} else {$text4 = addslashes(filter_var($_POST['text4'], FILTER_SANITIZE_STRING));}
				
if(isset($_POST['text5'])&&($_POST['text5']=="")){
$text5 = NULL;} else {$text5 = addslashes(filter_var($_POST['text5'], FILTER_SANITIZE_STRING));}
		
if(isset($_POST['text6'])&&($_POST['text6']=="")){
$text6 = NULL;} else {$text6 = addslashes(filter_var($_POST['text6'], FILTER_SANITIZE_STRING));}
Ma mi da questo errore :

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ',)' at line