adding values of a single column

how can i add all the values of one column of the table to get a total?

SELECT SUM(myColumn) FROM myTable WHERE 1

Note that the WHERE 1 is not necessary.

cool. now how do i store that sum in a variable?

I guess you are using php?

$sql = "SELECT SUM(myColumn) FROM myTable";
$result = mysql_query($sql);
list($sum) = mysql_fetch_row($result); // now $sum = 'the sum'