在lname下有3个名字，每次添加产品时这些名称和值都插入到其他表中，从那里我想通过分组名称来总结，还有如何通过限制日期和人名来安排它
riyas 1/1/2016 - car = 1
sara 2/1/2016 - bike = 2
riyas 3/1/2016 - car = 1
riyas 4/1/2016 - cycle = 10
sara 5/1/2016 - bike = 2
例如：car = 2，bike = 4，cycle = 10
<?php <$query_check_credentials = "SELECT lname SUM(af) AS total_amount FROM customer GROUP BY lname";$result = mysql_query($query_check_credentials); while($row = mysql_fetch_array( $result )){echo $row['total_amount'];}?>