mysql - 如何使用 MySql 中的单个查询按小时进行分割？

Question

假设我的 table 是这样的:

Sessions
start_dts (datetime)
end_dts (datetime)

数据看起来像这样:

start_dts             end_dts
12/25/2011 01:55:00   12/25/2011 03:30:00

我需要查询结果如下所示:

Date          Hour    MinutesOnline
12/25/2011    0       0
12/25/2011    1       5
12/25/2011    2       60
12/25/2011    3       30
... (every hour of the date range being queried)

这甚至可以通过单个查询实现吗？

Answer 1

这是一个很好的开始。这适用于任何日期/时间范围。但是，它有一个主要先决条件:您需要创建一个包含 dt_hr datetime 字段的 intervals 表，其中包含您正在扫描的所有时间间隔。

Ex: '2011-12-25 00:00:00',
    '2011-12-25 01:00:00',
    '2011-12-25 02:00:00',
    '2011-12-25 03:00:00',
          . . .
    '2011-12-25 23:00:00'

-

SELECT DATE_FORMAT(intervals.dt_hr,'%m/%d/%Y') AS Date,
       EXTRACT(HOUR FROM intervals.dt_hr) AS Hour,
       CASE 
          WHEN intervals.dt_hr > TIMESTAMPADD(HOUR,HOUR(s2.start_dts), DATE(s2.start_dts)) 
               AND intervals.dt_hr < TIMESTAMPADD(HOUR,HOUR(s2.end_dts), DATE(s2.end_dts))
            THEN 60
          WHEN intervals.dt_hr = TIMESTAMPADD(HOUR,HOUR(s2.start_dts), DATE(s2.start_dts)) 
               AND intervals.dt_hr < TIMESTAMPADD(HOUR,HOUR(s2.end_dts), DATE(s2.end_dts))
            THEN 60 - EXTRACT(MINUTE FROM s2.start_dts)
          WHEN intervals.dt_hr = TIMESTAMPADD(HOUR,HOUR(s2.end_dts), DATE(s2.end_dts))
               AND intervals.dt_hr > TIMESTAMPADD(HOUR,HOUR(s2.start_dts), DATE(s2.start_dts)) 
            THEN EXTRACT(MINUTE FROM s2.end_dts)
          WHEN intervals.dt_hr = TIMESTAMPADD(HOUR,HOUR(s2.start_dts), DATE(s2.start_dts)) 
               AND intervals.dt_hr = TIMESTAMPADD(HOUR,HOUR(s2.end_dts), DATE(s2.end_dts))
            THEN EXTRACT(MINUTE FROM s2.end_dts) - EXTRACT(MINUTE FROM s2.start_dts)
          ELSE 0
       END AS MinutesOnLine
FROM intervals
LEFT JOIN sessions s2 
  ON intervals.dt_hr >= TIMESTAMPADD(HOUR,HOUR(s2.start_dts), DATE(s2.start_dts)) 
    AND intervals.dt_hr <= TIMESTAMPADD(HOUR,HOUR(s2.end_dts), DATE(s2.end_dts))

要生成 intervals 表，您可以创建一个存储过程，该过程会创建一个带有 date_hour 序列的临时表。参见 Get a list of dates between two dates寻找一种方法来做到这一点。