您可以在MySQL查询中完全处理它：

SELECT SUM(column_name) FROM table_name;

在PHP代码中，尝试以下操作：

$result = mysql_query('SELECT SUM(value) AS value_sum FROM codes'); 
$row = mysql_fetch_assoc($result); 
$sum = $row['value_sum'];

使用PDO（mysql_query已弃用）

$stmt = $handler->prepare("SELECT SUM(value) AS value_sum FROM codes");
$stmt->execute();

$row = $stmt->fetchAll(PDO::FETCH_OBJ);
$sum = $row->value_sum;