我有一个包含捐赠的表格,我现在正在创建一个页面来查看统计信息。我想从数据库中获取月度数据,包括毛额和累计毛额。
mysql> describe donations;
+------------------+------------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+------------------+------------------+------+-----+---------+----------------+
| id | int(10) unsigned | NO | PRI | NULL | auto_increment |
| transaction_id | varchar(64) | NO | UNI | | |
| donor_email | varchar(255) | NO | | | |
| net | double | NO | | 0 | |
| gross | double | NO | | NULL | |
| original_request | text | NO | | NULL | |
| time | datetime | NO | | NULL | |
| claimed | tinyint(4) | NO | | NULL | |
+------------------+------------------+------+-----+---------+----------------+
这是我尝试过的:
SET @cgross = 0;
SELECT YEAR(`time`), MONTH(`time`), SUM(`gross`), (@cgross := @cgross + SUM(`gross`)) AS `cumulative_gross` FROM `donations` GROUP BY YEAR(`time`), MONTH(`time`);
结果是:
+--------------+---------------+--------------+------------------+
| YEAR(`time`) | MONTH(`time`) | SUM(`gross`) | cumulative_gross |
+--------------+---------------+--------------+------------------+
| 2013 | 1 | 257 | 257 |
| 2013 | 2 | 140 | 140 |
| 2013 | 3 | 311 | 311 |
| 2013 | 4 | 279 | 279 |
+--------------+---------------+--------------+------------------+
这是错误的。期望的结果是:
+--------------+---------------+--------------+------------------+
| YEAR(`time`) | MONTH(`time`) | SUM(`gross`) | cumulative_gross |
+--------------+---------------+--------------+------------------+
| 2013 | 1 | 257 | 257 |
| 2013 | 2 | 140 | 397 |
| 2013 | 3 | 311 | 708 |
| 2013 | 4 | 279 | 987 |
+--------------+---------------+--------------+------------------+
我在没有 SUM 的情况下尝试了这个,它确实按预期工作。
SET @cgross = 0;
SELECT YEAR(`time`), MONTH(`time`), SUM(`gross`), (@cgross := @cgross + 10) AS `cumulative_gross` FROM `donations` GROUP BY YEAR(`time`), MONTH(`time`);
+--------------+---------------+--------------+------------------+
| YEAR(`time`) | MONTH(`time`) | SUM(`gross`) | cumulative_gross |
+--------------+---------------+--------------+------------------+
| 2013 | 1 | 257 | 10 |
| 2013 | 2 | 140 | 20 |
| 2013 | 3 | 311 | 30 |
| 2013 | 4 | 279 | 40 |
+--------------+---------------+--------------+------------------+
为什么它不能与 SUM 一起使用?有什么办法可以解决吗?
谢谢, 拉西
最佳答案
没有变量的子查询同样容易,而且更便携;
SELECT YEAR(`time`),
MONTH(`time`),
SUM(gross),
(SELECT SUM(gross)
FROM donations
WHERE `time`<=MAX(a.`time`)) cumulative_gross
FROM donations a GROUP BY YEAR(`time`), MONTH(`time`);
关于mysql - 从 MySQL 表中获取累计总和,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/16322133/