$sql="select * from question_test where test_id='".$test_id."' and difficulty_level BETWEEN ".$_SESSION['difficulty_start']." and ".$_SESSION['difficulty_end']." and question_id NOT IN ('".implode("', '", array_map('mysqli_real_escape_string', $_SESSION['question_attempt']))."') order by rand()*favourability_level desc";
On running the above code I get an error :
Warning: mysqli_real_escape_string() expects exactly 2 parameters, 1 given in C:\xampp\htdocs\exam.php on line 359
Use a callback function instead
function array_map_callback($a)
{
global $con;
return mysqli_real_escape_string($con, $a);
}
array_map('array_map_callback', $_SESSION['question_attempt']);
where $con is the connection variable.
So your $sql variable would be:
$sql="select * from question_test where test_id='".$test_id."' and difficulty_level BETWEEN ".$_SESSION['difficulty_start']." and ".$_SESSION['difficulty_end']." and question_id NOT IN ('".implode("', '", array_map('array_map_callback', $_SESSION['question_attempt']))."') order by rand()*favourability_level desc";
or you can go with array_walk
array_walk($_SESSION['question_attempt'], function(&$string) use ($con) {
$string = mysqli_real_escape_string($con, $string);
});
array_map(function($a) use($con) { ...}, $_SESSION['question_attempt']).
