如何循环三维数组以将数据插入数据库？

This is my 3 dimensional array.

My $_POST array. These are the values

$_POST = Array ( 
[9] => Array ( [student_id] => 9 [subject_id] => 6 [class_id] => 2 [mark_obtained] => 40 [mark_obtainable] => 100 ) 
[10] => Array ( [student_id] => 10 [subject_id] => 6 [class_id] => 2 [mark_obtained] => 52 [mark_obtainable] => 100 ) 
[11] => Array ( [student_id] => 11 [subject_id] => 6 [class_id] => 2 [mark_obtained] => 30 [mark_obtainable] => 100 ) 
[12] => Array ( [student_id] => 12 [subject_id] => 6 [class_id] => 2 [mark_obtained] => 68 [mark_obtainable] => 100 ) )

How do i loop through it and submit each of the array into the database?

My column names are the keys. "student_id, subject_id, class_id, mark_obtained, mark_obtainable".

I am trying this but i keep getting duplicate entries.`foreach ($_POST as $i => $values1) {

foreach ($values1 as $key => $value) {
    $columns = implode(", ",array_keys($values1));
    $values  = implode(", ", $values1);
    $columns = $columns
    $sql = "INSERT INTO `daily_report`($columns) VALUES ($values)";

    if ($conn->multi_query($sql) === TRUE) {
        echo "New records created successfully <br>";
    } else {
        echo "Error: " . $sql . "<br>" . $conn->error;
    }
}

You have to echo the sql variable inside the foreach loop like this.

foreach ($_POST as $data => $values) {

echo $sql = "INSERT INTO `daily_report` (student_id, subject_id, class_id,mark_obtained,mark_obtainable,daily_report.date)
VALUES (".$values['student_id'].", ".$values['subject_id'].", ".$values['class_id'].", ".$values['mark_obtained'].",".$values['mark_obtainable'].", now())";

// echo $sqlupdate1 = "UPDATE table SET commodity_quantity=$qty WHERE user='".$rows['user']."' ";
if ($conn->query($sql) === TRUE) {
    echo "New record created successfully";
} else {
    echo "Error: " . $sql . "<br>" . $conn->error;
}

Concatenate the variables while echoing.

You don't need a 3 dimensional array. You can use a 2 dimensional array and by using foreach you can insert them one by one. Here is an example:

 $data_array = [
    [
        'student_id' => 9,
        'subject_id' => 6, 
        'class_id' => 2,
        'mark_obtained' => 40,
        'mark_obtainable' => 100    
    ],
        [
        'student_id' => 10,
        'subject_id' => 6, 
        'class_id' => 2,
        'mark_obtained' => 52,
        'mark_obtainable' => 100    
    ],
        [
        'student_id' => 11,
        'subject_id' => 6, 
        'class_id' => 2,
        'mark_obtained' => 30,
        'mark_obtainable' => 100    
    ],
        [
        'student_id' => 12,
        'subject_id' => 6, 
        'class_id' => 2,
        'mark_obtained' => 30,
        'mark_obtainable' => 100    
    ],
];

foreach($data_array as $data) {
$sql = "INSERT INTO `daily_report` (student_id, subject_id, class_id,mark_obtained,mark_obtainable)
VALUES ($data['student_id'], $data['subject_id'], $data['class_id'], $data['mark_obtained'],$data['mark_obtainable'])";
if ($conn->query($sql) === TRUE) {
    echo "New record created successfully";
} else {
    echo "Error: " . $sql . "<br>" . $conn->error;
}