sum()函数计算时间

Question

mysql 用sum(liezhi)  -->leizhi是time类型。当好像计算出的结果不正确，不知道是怎么回事？

Answer 1

select sum(total_time) from balance_conf_account where start_time>'2007-01-01  00:00:00' and end_time<'2009-01-01  00:00:00
' and end_time!='0000-00-00 00:00:00' and card_index=1;
+-----------------+
| sum(total_time) |
+-----------------+
|            8446 |
+-----------------+
1 row in set
mysql> 
select SECOND
(total_time) from balance_conf_account where start_time>'2007-01-01  00:00:00' and end_time<'2009-01-01  00:00:00' and end_time!='0000-00-00 00:00:00' and card_index=1;
+--------------------+
| SECOND(total_time) |
+--------------------+
|                  0 |
|                 50 |
|                 12 |
|                 42 |
|                 42 |
+--------------------+
5 rows in set
mysql> 
select MINUTE
(total_time) from balance_conf_account where start_time>'2007-01-01  00:00:00' and end_time<'2009-01-01  00:00:00' and end_time!='0000-00-00 00:00:00' and card_index=1;
+--------------------+
| MINUTE(total_time) |
+--------------------+
|                 43 |
|                 20 |
|                 10 |
|                 10 |
|                  0 |
+--------------------+select HOUR
(total_time) from balance_conf_account where start_time>'2007-01-01  00:00:00' and end_time<'2009-01-01  00:00:00' and end_time!='0000-00-00 00:00:00' and card_index=1;
+------------------+
| HOUR(total_time) |
+------------------+
|                0 |
|                0 |
|                0 |
|                0 |
|                0 |
+------------------+
用第一种是8000多秒第二,第三，第四的总和才5000多点。、不知是怎么回事？

Answer 2

哦，我知道了。mysql漏洞：他那个分钟时乘以100的，不是60.