create average value

I'm doing a rating function and got a little stucked on the php.
I'm trying to send a value from flash to php, take that value and put it in a database.
I was thinking that I should have three rows in my table: ID, votes_sum and votes_tot. So that I can calculate an average value.

The ID should represent the specific movie or what I'm rating on, votes_sum should be a value that increases depending of the value the php recieves. And the votes_sum should count how many votes have been made on that specific ID.
So far I only figured out something like this, but I dont really know if I'm on the right track.. (I'm not so experienced in php) any ideas?

<?php 
$DBhost = "localhost"; // Database Server 
$DBuser = "user"; // Database User 
$DBpass = "pass"; // Database Pass 
$DBName = "database"; // Database Name 
$table = "table"; // Database Table 

// Recieve Variables From Flash 
$rate_value = $_POST['valueToPHP']; 
$name = $_POST['nameToPHP']; 

// Insert the data into the mysql table 
$sql = 'INSERT INTO ' . $table . 
' (`ID`, 
`votes_summa`, 
`votes_total` 
) 
VALUES 
('' . $name . '',' 
. ''' . $rate_value . '' 
)'; 
?>

Code (markup):

 

looks ok but first you need to connect to the db

$dbh = mysql_connect($hostname, $username, $password)
or die("Unable to connect to mysql");

$selected = mysql_select_db($DBName,$dbh)
or die("Could not select ".$DBName);

$sql = 'INSERT INTO ' . $table . ' (ID, votes_summa,votes_total) VALUES ('' . $name . '',' .''' . $rate_value . '' )';


if (mysql_query($sql)) {
print "successfully inserted record";
}
else {
print "Failed to insert record";
}
mysql_close($dbh);

 

you can use:

SELECT avg(vote_points) as average where something=is_something

avg() gets the average of all the values in the result..