how to update two records from different table in one query?
Question
I'm building my e-commerce project for school, but i'm facing a problem. How to reduce stock automatically and change the order status in one query?
here's my database :
table orders: id | customer_id | date | status | total
table orderitems: id | order_id | product_id | quantity
table products: id | category | name | description | image | price | stock
Here's the code for viewing records from table orders :
<?php session_start();
ob_start();
if(ISSET($_SESSION['SESS_ADMINLOGGEDIN'])){
}
else{
header("location: login.php");
}
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http:// www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html;charset=iso-8859-1" / >
<link rel="stylesheet" href="css/style_admin.css" type="text/css" />
<title>Untitled Document</title>
</head>
<body>
<?php
require("../config.php");
require("../functions.php");
if(!isset($_SESSION['SESS_ADMINLOGGEDIN'])) {
header("Location: " . $config_basedir);
}
if(isset($_GET['func']) == TRUE) {
$funcsql = "UPDATE orders SET status = 10 WHERE id = " . $_GET['id'];
mysql_query($funcsql);
header("Location: orders.php");
}
else {
require("header.php");
echo "<h1>Outstanding orders</h1>";
$orderssql = "SELECT * FROM orders WHERE status = 2";
$ordersres = mysql_query($orderssql);
$numrows = mysql_num_rows($ordersres);
if($numrows == 0)
{
echo "<strong>No orders</strong>";
}
else
{
echo "<table cellspacing=10>";
while($row = mysql_fetch_assoc($ordersres))
{
echo "<tr>";
echo "<td>[<a href='adminorderdetails.php?id=" . $row['id']. "'>View</ a>]</td>";
echo "<td>". date("D jS F Y g.iA", strtotime($row['date'])). "</td>";
echo "<td>";
if($row['registered'] == 1)
{
echo "Registered Customer";
}
else
{
echo "Non-Registered Customer";
}
echo "</td>";
echo "<td>Rp. ;" . sprintf('%.2f',
$row['total']) . "</td>";
echo "<td>";
if($row['payment_type'] == 1)
{
echo "PayPal";
}
else
{
echo "Cheque";
}
echo "</td>";
echo "<td><a href='orders.php?func=conf&id=" . $row['id']. "'>Confirm Payment</a></td>";
echo "</tr>";
}
echo "</table>";
}
}
?>
</body>
</html>
i'm successful for updating status to '10' but i want to reduce stock by stock from table products - quantity from table orderitems when the administrator click the 'Confirm Payment'.
2 answers
solution1
3 ACCPTED 2015-05-15 06:22:37
You can do it like the sample code below.
Assume there are two tables.
Table 1
create table db1 (
username varchar(10),
user_level integer
);
Table 2
create table db2 (
username varchar(10),
user_level integer
);
For sample data inserting few records with values.
insert into db1 values ('a', 0), ('b', 2), ('c', 3);
insert into db2 values ('a', 2), ('b', 1), ('c', 3);
Here is the single query which you asked for as sample below
update db1 inner join db2 on db1.username = db2.username
set db1.user_level = 6,
db2.user_level = 5
where db1.username = 'a';
solution2
0 2015-05-02 19:07:00
You can´t update different tables in the same query. If you want to do so and prevent an inconsistency in the db because of the 2nd update failing you should use transactions otherwise you should use 2 queries. You can implement transactions in your code, you may implement a trigger on update or you can create a stored procedure in the DB.
Wish i made myself clear and it helps!
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