# 阶段等待时间对比（A）

![left](./student-guide/diagram/27-Waiting-time-comparison-01-01.png)
![right](./student-guide/diagram/27-Waiting-time-comparison-01-02.png)

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20:00 ~ 21:00 SQL 执行耗时
21:20 ~ 22:30 SQL 执行耗时