How to calculate the sum of variables in PHP - php

Question

It calculates, but starting from the second row.
<?php
include('connect-db.php');
$query = "select * from users";
$result = mysql_query($query);
$row = mysql_fetch_array($result);
$sold= array();
while ($row = mysql_fetch_array($result, MYSQL_ASSOC)) {
$sold=$row['contract']+$row['tva'];
echo "<table><tr><td>" . $sold. "</td></tr></table>";
}
?>

Answer 1

Your code has many issues:
Your code starts to calculate from the second row because of the line:
$row = mysql_fetch_array($result);
which obtains the first result from the opened recordset before the while loop.
$sold = array();Why is that an array?
If you want to sum to $sold, threat the variable as an integer and initialize it with a 0.
$sold = 0;
while ($row = mysql_fetch_array($result, MYSQL_ASSOC))
$sold += $row['contract']+$row['tva'];
echo "<table><tr><td>" . $sold. "</td></tr></table>";
It seems to me also that you may want to print the table only once. If this is true, consider to query the database with an aggregation function like SUM():
SELECT SUM(contract + iva) AS contractIva FROM users GROUP BY <some column in your table>;
The above allows to remove the while loop.

Answer 2

Since you already extracted a row from the result, with $row = mysql_fetch_array($result);, the script starts adding only with the next row. Th correct code would be:
<?php
include('connect-db.php');
$query = "select * from users";
$result = mysql_query($query);
$sold= array();
while ($row = mysql_fetch_array($result, MYSQL_ASSOC)) {
$sold=$row['contract']+$row['tva'];
echo "<table><tr>
<td>" . $sold. "</td>
</tr></table>";
}
?>

Answer 3

you can do that via query as well so that you don't need to perform calculation on the application level, database level can do this job for you.
select sum(col1+col2) as total from users
And you want one table instead of multiple tables I guess, if yes then do it like this:
echo "<table>
while ($row = mysql_fetch_array($result, MYSQL_ASSOC)) {
$sold=$row['contract']+$row['tva'];
echo <tr><td>" . $sold. "</td></tr>";
}
echo "</table>";