Question

我有一个名为Thermo的表，每30分钟存储两个不同的温度

（dt =时间| Ti =内部温度| To =外部温度）

我想交替获取白天和黑夜的平均值。这可以通过分组小时 06：00-17：59 和 18：00-05：59

我能做的最好的就是按照以下代码对00：00-11：59和12：00-23：59进行分组：

SELECT CAST(strftime('%m%d', dt) AS TIME) || CAST(strftime('%H', dt)/12 AS TIME) AS time,
  round(avg(Ti), 1) AS Ti,
  round(avg(To), 1) AS To,
  FROM thermo WHERE dt > datetime(CURRENT_TIMESTAMP, 'localtime', '-10 days')
  GROUP BY time ORDER BY time;

是否可以改变时间组？

Answer 1

您可以使用CASE来确定感兴趣的时间段：

SELECT CAST(strftime('%m%d', dt) AS TIME) as dt,
       (CASE WHEN strftime('%H', dt) BETWEEN 6 AND 17 THEN 'daytime'
             ELSE 'nightime'
         END) as period,
       round(avg(Ti), 1) as Ti,
       round(avg(To), 1) as To
FROM thermo
WHERE dt > datetime(CURRENT_TIMESTAMP, 'localtime', '-10 days')
GROUP BY dt, period
ORDER BY time;

如何通过每天（白天/晚上）进行两个小组来获得小组的平均值？

1 个答案: