How to Generate Random number without repeat in database using PHP?

Question

I would like to generate a 5 digit number which do not repeat inside the database. Say I have a table named numbers_mst with field named my_number

Answer 1

We can simply do with this:

$regenerateNumber = true;

do {
    $regNum      = rand(2200000, 2299999);
    $checkRegNum = "SELECT * FROM teachers WHERE teacherRegNum = '$regNum'";
    $result      = mysqli_query($connection, $checkRegNum);

    if (mysqli_num_rows($result) == 0) {
        $regenerateNumber = false;
    }
} while ($regenerateNumber);

$regNum will have the value which is not present in the database