如何使用预准备语句插入多行

I use a very simple insert statement

INSERT INTO table (col1, col2, col3) VALUES (1,2,3), (4,5,6), (7,8,9), ...

Currently, the part of the query that holds the values to be inserted is a separate string constructed in a loop.

How can I insert multiple rows using a prepared statement?

edit: I found this piece of code. However, this executes a seperate query for every row. That is not what I am looking for.

$stmt =  $mysqli->stmt_init();
if ($stmt->prepare("INSERT INTO table (col1, col2, col3) VALUES (?,?,?)")){ 
    $stmt->bind_param('iii', $_val1, $_val2, $_val3);
    foreach( $insertedata as $data ){
        $_val1 = $data['val1'];
        $_val2 = $data['val2'];
        $_val3 = $data['val3'];
        $stmt->execute();
    }
}

edit#2: My values come from a multidimensional array of variable length.

$values = array( array(1,2,3), array(4,5,6), array(7,8,9), ... );

This is normally only a technique that I use when I am writing a prepared statement for a query that contains an IN clause. Anyhow, I've adapted it to form a single prepared query (instead of iterated prepared queries) and I tested it to be successful on my server. The process is a bit convoluted and I don't know if there will ever be any advantage in speed (didn't benchmark). This really isn't the type of thing that developers bother with in production.

Code:

if (!$mysqli = new mysqli($config[0], $config[1], $config[2], $config[3])) {
    echo "connection bonk";
} else {
    $array = [[1, 2, 3],[4, 5, 6], [7, 8, 9]];  // sample indexed array of indexed arrays
    $params = [];
    foreach ($array as $row) {
        $parentheticals[] = '('.implode(',', array_fill(0, sizeof($row), '?')).')';  // build parentheticals
        $params = array_merge($params, $row);  // flatten actual values to 1-dim array
    }
    $values = implode(',', $parentheticals);
    $count = sizeof($params); // assuming you have balanced subarrays

    if ($stmt = $mysqli->prepare("INSERT INTO test (col1, col2, col3) VALUES $values")) {
        array_unshift($params, str_repeat('i', $count));  // prepend the type values string
        $ref = [];  // add references
        foreach ($params as $i=>$v) {
            $ref[$i] = &$params[$i];  // pass by reference as required/advised by the manual
        }
        call_user_func_array([$stmt, 'bind_param'], $ref);    

        if ($stmt->execute()) {
            echo $stmt->affected_rows , " affected rows";  // how many rows were inserted
        } else {
            echo "execution bonk";
        }
        $stmt->close();
    } else {
        echo "prepare bonk";
    }
}