测试环境的MySQL错误日志里面，出现警告信息
[Warning] Unsafe statement written to the binary log

180510 11:15:00 [Warning] Unsafe statement written to the binary log using statement format since BINLOG_FORMAT = STATEMENT. Statements writing to a table with an auto-increment column after selecting from another table are unsafe because the order in which rows are retrieved determines what (if any) rows will be written. This order cannot be predicted and may differ on master and the slave. Statement: UPDATE ls_klass_subject ksubj
JOIN (
SELECT classSubjId, SUM(count) AS endCount
FROM ls_lesson
WHERE isDeleted = 0
AND isEnd = 0
AND endTime < DATE_ADD(NOW(), INTERVAL -30 MINUTE)
GROUP BY classSubjId
) t
SET finish = IFNULL(finish,0)+ t.endCount,
modifiedBy =888,
modifiedOn = NOW()
WHERE ksubj.classSubjId =t.classSubjId AND ksubj.isDeleted = 0

报错原因：
数据库的二进制日志格式为语句，在SQL语句中有DATE_ADD(NOW(), INTERVAL -30 MINUTE)时间函数。
这样会导致从库上面的语句执行结果可能不一致。

解决方法：
将二进制日志的格式设为ROW或MIXED。

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MySQL日志警告'[Warning] Unsafe statement written to the binary log'