how to select id from one table and insert into other table - php

Question

$select = "SELECT MAX(order_id) FROM `order`";
mysql_query($select);
foreach ($_COOKIE['item'] as $key12 => $value) {
$value22 = explode("__", $value);
$query1 = "INSERT INTO `cart`(`cart_id`, `product_id`, `order_id`, `Quantity`, `total_price`) VALUES ('',$value22[5],'$select','$value22[3]','$value22[4]')";
$result2 = mysql_query($query1);
The output of this is SELECT MAX(order_id) FROM order, so what is the solution of this selection and insertion of the id

Answer 1

$select="SELECT MAX(order_id) FROM `order`";
$row = mysqli_query($con,$select);
if(mysqli_num_rows($row)>0)
{
while($data = mysqli_fetch_assoc($row))
{
$order_id = $data['order_id'];
}
}
//This way you can fetch data
Then use this while inserting value for order_id in your query as in
$query1="INSERT INTO `cart`(`cart_id`, `product_id`, `order_id`, `Quantity`, `total_price`) VALUES ('',$value22[5],'$select','$order_id','$value22[4]')";

Answer 2

one another way to find last inserted id from the db connection:
mysql_query('INSERT INTO order(a) VALUES('b'));
$id = mysql_insert_id();
then $id will be last inserted id

Answer 3

Recommendation:
Use only one batch INSERT query. It gives you the opportunity to insert multiple rows at once, e.g. by running only one query. And is a lot faster.
Used method:
Extract maximum of order_id from order and assign to $maxOrderId.
Iterate through cookie items and build corresponding rows
part of the INSERT sql statement. Then add it to the array $insertRowValues.
In the end implode the $insertRowValues array into the batch INSERT statement.
Run the batch INSERT query - only once.
<?php
$select = "SELECT MAX(order_id) FROM `order`";
$maxOrderId = mysql_query($select);
$insertRowValues = array();
foreach ($_COOKIE['item'] as $key12 => $value) {
$value22 = explode("__", $value);
$insertRowValues[] = "('', " . $value22[5] . ", '" . $maxOrderId . "', '" . $value22[3] . "', '" . $value22[4] . "')";
}
$query1 = "INSERT INTO `cart`
(`cart_id`, `product_id`, `order_id`, `Quantity`, `total_price`)
VALUES " . implode(', ', $insertRowValues);
$result2 = mysql_query($query1);
Other recommendations:
Use mysqli or PDO instead of mysql, because mysql is already removed as of PHP 5.5.0 (see MySQL Library - Introduction);
Use exception handling;
Use prepared statements to avoid MySQL injection.
P.S: I couldn't test anything.
Good luck!