在 MySQL 中选择按小时分组的日期/时间分组

Question

我在 mysql 表中有一堆日期数据，如下所示：

2010-02-13 1:00:00, "soma data"
2010-02-13 1:25:00, "soma data"
2010-02-13 1:37:00, "soma data"
2010-02-13 2:12:00, "soma data"

我想选择一个显示按小时分组的数据的报告，例如：

On Feb 13, during the hour from 1:00 pm to 1:59 pm, there were 3 data points.
On Feb 13, during the hour from 2:00 pm to 2:59 pm, there was 1 data points.
...

基本上我想报告一天中每个小时发生的累积记录数量。所以最终结果会给我一个 10 天的报告，以 24 小时为增量细分，这样我就可以看到在任何给定日期的任何给定小时内有多少数据。

TIA，希望你能帮上忙！

Answer 1

您可能希望在以下查询中使用GROUP BY 子句：

SELECT 
    COUNT(*),
    YEAR(dateTimeField),
    MONTH(dateTimeField),
    DAY(dateTimeField),
    HOUR(dateTimeField)
FROM 
    yourTable
WHERE
    dateTimeField >= '2010-02-04 00:00:00' AND
    dateTimeField < '2010-02-14 00:00:00'
GROUP BY 
    YEAR(dateTimeField), 
    MONTH(dateTimeField),
    DAY(dateTimeField),
    HOUR(dateTimeField);

您可能还想查看 MySQL 文档以获取有关日期和时间函数的更多参考：

• MySQL 5.1 Reference Manual - Date and Time Functions

Answer 2

SELECT HOUR(datetime), COUNT(*)
FROM table
GROUP BY HOUR(datetime);

您将获得两个字段：小时和该小时内的事件数。