Mysql 查询一天中每半小时记录的数量

SELECT HOUR(e.time)as Hour,FLOOR(MINUTE(e.time)/30) as M, COUNT(*) as Count FROM error_log e 
WHERE e.date = '2017-09-02' GROUP BY FLOOR(MINUTE(e.time)/30),HOUR(e.time) ORDER BY Hour(e.time);

floor函数是mysql 的向下取整函数 如 floor(1.2) = 1

以下是运行结果：

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