store multiple value with same input name in sql - php

Question

I need to insert the value of form into the data table.
here is my form for taking a test.
<form method="post" action="">
1<input type="text" name="answer">
3<input type="text" name="answer">
5<input type="text" name="answer">
7<input type="text" name="answer">
<input type="submit" name="submit">
</form>
how to store this all answer in one field of the data table
i have tried this code but its not storing all value
if(isset($_POST['submit']))
{
$answer = json_encode($_POST['answer']);
$query = "INSERT INTO `test` (`answer`) VALUES ('$answer')";
mysqli_query($con, $query);
if (mysqli_query($con, $query)) {
echo "inserted ";
} else {
echo "Error updating record: " . mysqli_error($con);
}
}

Answer 1

Try changing your HTML code to this.
<form method="post" action="">
1<input type="text" name="answer[]">
3<input type="text" name="answer[]">
5<input type="text" name="answer[]">
7<input type="text" name="answer[]">
<input type="submit" name="submit">
</form>
When you submit the form the $_POST['answer'] would look something like this
Array
(
[answer] => Array
(
[0] => first answer
[1] => second answer
[2] => third answer
[3] => fourth answer
)
)
Above is a printout of $_POST variable like so print_r($_POST)
Now you can easily get all the answer inputs inside PHP and have it converted to json like so
$answer = json_encode($_POST['answer']);
However since you are saving this inside mysql I would suggest using serialize() instead of json_encode(). Please read about serialize() https://www.php.net/manual/en/function.serialize.php