Sqlite 避免重复子查询

我有一个表messages，其中包含一列message\u internaldate。现在，我想计算几个月内特定时间段（每天每小时）内的消息数。我可以通过大量的子查询（24）来获得每小时的消息总数，但我希望有一种更聪明的方法来做到这一点。子查询类似，只是时间段发生了变化。有什么建议吗

e、 前两个小时

SELECT T1, T2 FROM 
(
SELECT sum(T1c) as T1 FROM
    (
    SELECT strftime('%H:%M',message_internaldate) AS T1s ,count(*) as T1c FROM messages WHERE
    message_internaldate BETWEEN '2005-01-01 00:00:00' AND '2012-12-31 00:00:00'
    AND strftime('%H:%M',message_internaldate) BETWEEN '01:00'AND '01:59'
    GROUP BY strftime('%H:%M',message_internaldate)
    )
)
,
(
SELECT sum(T2c) as T2 FROM
    (
    SELECT strftime('%H:%M',message_internaldate) AS T2s ,count(*) as T2c FROM messages WHERE
    message_internaldate BETWEEN '2005-01-01 00:00:00' AND '2012-12-31 00:00:00'
    AND strftime('%H:%M',message_internaldate) BETWEEN '02:00'AND '02:59'
    GROUP BY strftime('%H:%M',message_internaldate)
    )
)
...

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您的问题是希望将各个小时作为列

要将它们作为行，请尝试以下查询：

SELECT strftime('%H', message_internaldate) AS hour,
       strftime('%H:%M', message_internaldate) AS Ts,
       COUNT(*) AS Tc
FROM messages
WHERE message_internaldate BETWEEN '2005-01-01 00:00:00' AND '2012-12-31 23:59:59'
GROUP BY 1, 2

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谢谢我补充道：按小时从（您的查询）组中选择hour，sum（Tc）作为SumOfMails，这正是我最初想要做的！