Select a specific cell from table

Question

I know it must be something very silly I'm missing here. I have a table and all calculations are working great. I'm stuck here:

After while loop I can echo ttl_sold and all other information everything except "balance".

in while loop these are fine and I get results:

$sql="SELECT * FROM $tbl_name";
$result=mysql_query($sql); ?>

<?php
$sum = $sum + $rows['total'];
$ttlsold = $ttlsold + $rows['quantity'];
?>


<?php

$sum = 0;
$ttlsold = 0;

while($rows=mysql_fetch_array($result)){

ttl_sold is 12 and when I echo "balance" I get -12. I did try to include this within the loop and outside, but still no luck!

<?php
$balance = "SELECT stock FROM tbl_name WHERE id = 1";
$balance = $balance - $ttl_sold;
?>

<table width="1000" border="1" cellspacing="0" cellpadding="3">
<tr>
<td width="100"><?php echo $balance; ?></td>

Any idea? Thanks!

$balance is the SQL statement as a string variable.... you're not executing the SQL query or getting the result... suggest you look at the PHP manual for the basics of database access.... and learn PDO (http://www.php.net/manual/en/book.pdo.php) rather than the deprecated MySQL that most people will suggest — Mark Baker, Feb 17 '13 at 11:06
Please show us the entire relevant code, including the part where you execute the query and the loop you speak of. — Tim Post, Feb 17 '13 at 11:11

score 2 · Answer 1 · edited May 23 '17 at 12:12

2

try this,

$query = "SELECT stock FROM tbl_name WHERE id = 1";
$result = mysql_query($query);
while ($row = mysql_fetch_assoc($result))
{
    $balance = $row['stock'];
    $balance = $balance - $ttl_sold;
}

mysql_query

The article below talks about SQL Injection but it introduces how to use new PHP Extensions such as PDO and MySQLi.

How to prevent SQL injection in PHP?

edited May 23 '17 at 12:12

Community

1
1

answered Feb 17 '13 at 11:08

John Woo

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3

mysql_* is deprecated, why not to tell beginners about mysqli? – sybear Feb 17 '13 at 11:10
As I suspected, he actually _is_ executing the query (he just edited) – Tim Post Feb 17 '13 at 12:05
Thanks all. I got it done. I actually had to run 2 queries at the same time before the while loop. – StillTrying Feb 17 '13 at 12:28

score 1 · Answer 2 · answered Feb 17 '13 at 11:13

You are doing something like this:

$balance = "SELECT stock FROM tbl_name WHERE id = 1" - 12;
// PHP makes:
$balance = (int) "SELECT stock FROM tbl_name WHERE id = 1" - 12;
// And moreover:
$balance = 0 - 12;
$balance = -12;

You have to execute this query first, for MySQL you can use PDO or MySQLi.

Select a specific cell from table

2 Answers2