mysql中的触发器插入多行而不是一行

Question

我试图将来自4个不同表的4列总和插入到一个单独的表（名为bugs）触发器中，如下所示：

SELECT 
    uat_reopened_stats.release_name,
    (uat_reopened_stats.rate_bugs + qa_reopened_stats.rate_bugs + closed_reopened_stats.rate_bugs + done_reopened_stats.rate_bugs)
INTO @releasename, @bugstotalreopenrate  
FROM qa_reopened_stats
JOIN uat_reopened_stats 
    ON qa_reopened_stats.release_name = uat_reopened_stats.release_name
JOIN closed_reopened_stats 
    ON closed_reopened_stats.release_name = uat_reopened_stats.release_name
JOIN done_reopened_stats 
    ON done_reopened_stats.release_name = uat_reopened_stats.release_name;

INSERT INTO release_stats (release_name, bugs_total_reopen_rate)
VALUES (@releasename, @bugstotalreopenrate)
ON DUPLICATE KEY UPDATE 
    release_name=@releasename,
    bugs_total_reopen_rate=@bugstotalreopenrate;
END

但是，当执行触发器时（事先将release_stats表清空），最后我得到的行有11（！）行！

MySQL [jira_statistics]> select * from release_stats;
+--------------+------------------------+
| release_name | bugs_total_reopen_rate |
+--------------+------------------------+
| 2.3.0        | 9.090909004211426      |
| 2.3.0        | 9.090909004211426      |
| 2.3.0        | 9.090909004211426      |
| 2.3.0        | 9.090909004211426      |
| 2.3.0        | 9.090909004211426      |
| 2.3.0        | 9.090909004211426      |
| 2.3.0        | 9.090909004211426      |
| 2.3.0        | 9.090909004211426      |
| 2.3.0        | 9.090909004211426      |
| 2.3.0        | 9.090909004211426      |
| 2.3.0        | 9.090909004211426      |
+--------------+------------------------+

为什么会这样？

Answer 1

由于某种原因，在将release_name设置为表release_stats的主键后，问题消失了。