Combining two PHP variables for MySQL query - php

Question

I have a variable formvar that is incremented every time a user adds an additional field in an HTML form. This variable is posted to the PHP script for the purpose of looping through all of the added fields.
I am trying to combine two variables in the MySQL query to match what is in my HTML form. I would like the MySQL query to go upc0, upc1, etc until the for loop terminates.
for($i=0;$i<=$_POST[formvar];$i++)
{
mysql_select_db("bits", $con);
$sql="INSERT INTO report (UPC, Quantity, Comment)
VALUES ('$_POST[upc].$i','$_POST[quantity].$i','$_POST[comment].$i')";
if (!mysql_query($sql,$con))
{
die('Error: ' . mysql_error());
}
else echo "Records added successfully";
}
Sorry if this code is bad, I am new to web programming.
Thank you!

Answer 1

Ok, since each answer hinted at escaping (but did not give an example):
$sql = "INSERT INTO report (UPC, Quantity, Comment) VALUES
('" . mysql_real_escape_string($_POST["upc".$i]) . "','" .
mysql_real_escape_string($_POST["quantity" . $i]) . "','" .
mysql_real_escape_string($_POST["comment" . $i]) . "')";
That should protect you from SQL Injection, and is one proper method of creating sql queries. The best method would be to use parametrized queries (There's a ton of information out there on it, so I'd suggest a good Google search would be better than me trying to explain it here)...

Answer 2

First things first. In your HTML, create Input-Fields like this:
<input type="foo" name="upc[]">
<input type="foo" name="quantity[]">
<input type="foo" name="comment[]">
Then in your PHP-Script you do it like this:
<?php
# Choose DB
mysql_select_db("bits", $con);
# Iterates the Form-Data
$data_arr = array();
foreach($_POST['upc'] as $k=>$v) {
# Makes sure all needed data is available
if(isset($_POST['quantity'][$k], $_POST['comment'][$k])) {
$data_arr[] = array(
'upc' => $v,
'quantity' => $_POST['quantity'][$k],
'comment' => $_POST['comment'][$k]
);
}
}
# Build mysql insert string
foreach($data_arr as $k=>$v) {
# Escapes each field
$v = array_map('mysql_real_escape_string', $v);
# Maps array to value set
$data_arr[$k] = '('. implode(',', $v). ')';
}
$sql = 'INSERT INTO report (UPC, Quantity, Comment) VALUES '. implode(', ', $data_arr);
# Perform mysql query
mysql_query($sql, $con) or die('Error: ' . mysql_error());
echo 'Records added successfully';
Wrote it on my iPad, i'm on an airplane... so untestet. Good luck. ;o)

Answer 3

Not sure if I understand the question well but this is what I think :
$sql="INSERT INTO report (UPC, Quantity, Comment) VALUES
('" . $_POST["upc".$i] . "','" . $_POST["quantity" . $i] . "','" . $_POST["comment" . $i] . "')";
Note : this is a short version, you must add mysql_real_escape_string, etc, etc.
Also I supposed every variable could be string so I surrounded them by ''.
$_POST["name" . $i] let you loop throught POST variables starting with the name "name" followed by a number, this must be inserted into your for loop.

Answer 4

As recipes are so acclaimed I'm going to give my own, concerning the actual question:
<?php
for ($i=0; $i<=$_POST['formvar']; ++$i) {
mysql_select_db("bits", $con);
$v = array_map(mysql_real_escape_string(array(_POST["upc{$i}"], $_POST["quantity{$i}"], $_POST["comment{$i}"])));
$sql = "INSERT INTO report (UPC, Quantity, Comment) VALUES('"
. implode("', '", $v)
. "')";
if (!mysql_query($sql,$con)) {
trigger_error(html_entities('Error: ' . mysql_error()));
}
}
?>