php数学问题

I have a db table which have a row of a product amount. I want to create a loop that will calculate for me the sum for all the amounts.

$results = mysql_query("SELECT * 
                         FROM prod");

while($info = mysql_fetch_array($results)) {    
  $amount = $info['amount'];
}

amount is the var for each product cost. I want to get a sum for all the vars together - how can I do it?

Use the SUM() function in a SQL query.

$result = mysql_query("SELECT SUM(amount) AS sum_amount FROM prod");

if ( $result )
    $sum = mysql_result($result, 0, 0);

Easier to do in MySQL:

SELECT SUM(amount) FROM prod

Then fetch the result.

First:

You can do this with mysql

SELECT SUM(amount) FROM ....

Second:

while ($info = mysql_fetch_array($results)) {
    $amount[] = $info['amount'];
}

$sum = array_sum($amount);

You can add the amounts to a variable:

$results = mysql_query("select * from prod");

$sum = 0
while($info = mysql_fetch_array($results)) {
    $amount = $info['amount'];
    $sum += $amount
}

Or you can do it in SQL:

SELECT SUM(column) FROM table