How do you use bind_params for a timestamp data? - php

Question

I am trying to get data on a database between two timestamps and I have seen many posts that use the BETWEEN. But I can't get past the error that is related to my bindparams that's why I can't test the codes that I saw on another post.
About the first part of my code, I just thought that the value on $date1 and $date2 is a string and I thought that maybe I need it to be converted to a MySQL timestamp format so I used the following code.
How do I use bindparams on a timestamp based on my code?
I tried the following code but I keep getting an error on POSTMAN.
such as Number of variables doesn't match the number of parameters
This is the sample value for date1 and date 2 that I am using on Postman for testing
$date1 is 2019-12-13 00:00:00
$date2 is 2019-12-15 00:00:00
DbOperation.php
//view cart product sales in cartData via date
public function viewCartDatabyDate($date1, $date2){
$timestamp1 = strtotime($date1);
$timestamp2 = strtotime($date2);
$newDate1=date("Y-m-d H:i:s", $timestamp1);
$newDate2=date("Y-m-d H:i:s", $timestamp2);
$stmt = $this->con->prepare("SELECT * FROM cart_data WHERE created BETWEEN '$newDate1' AND '$newDate2' ORDER BY created");
//$stmt->bind_param("s", $newDate1);
//$stmt->bind_param("s", $newDate2);
$stmt->bind_param("s", $created);
$result = $stmt->get_result();
while($data = $result->fetch_assoc()){
$cartdata[]=$data;
}
return $cartdata;
}

Answer 1

You need to use placeholders. Question marks in SQL mean that this is the place where the variable is attached.
$stmt = $this->con->prepare("SELECT * FROM cart_data WHERE created BETWEEN ? AND ? ORDER BY created");
$stmt->bind_param("ss", $newDate1, $newDate2);
$result = $stmt->get_result();
$certdata = $result->fetch_all(MYSQLI_ASSOC);