[英]DateTime group by date and hour
我有一個名為activity_dt的日期時間,數據如下所示:
2/5/2013 9:24:00 AM
2/7/2013 7:17:00 AM
我如何按日期和時間分組?
SQL 服務器:
SELECT [activity_dt], count(*)
FROM table1
GROUP BY DATEPART(day, [activity_dt]), DATEPART(hour, [activity_dt]);
甲骨文:
SELECT [activity_dt], count(*)
FROM table1
GROUP BY TO_CHAR(activity_dt, 'DD'), TO_CHAR(activity_dt, 'hh');
MySQL:
SELECT [activity_dt], count(*)
FROM table1
GROUP BY hour( activity_dt ) , day( activity_dt )
使用 MySQL 我通常這樣做:
SELECT count( id ), ...
FROM quote_data
GROUP BY date_format( your_date_column, '%Y%m%d%H' )
order by your_date_column desc;
或者以同樣的想法,如果您需要輸出日期/小時:
SELECT count( id ) , date_format( your_date_column, '%Y-%m-%d %H' ) as my_date
FROM your_table
GROUP BY my_date
order by your_date_column desc;
如果您在日期列上指定索引,MySQL 應該能夠使用它來稍微加快速度。
SELECT [activity_dt], COUNT(*) as [Count]
FROM
(SELECT dateadd(hh, datediff(hh, '20010101', [activity_dt]), '20010101') as [activity_dt]
FROM table) abc
GROUP BY [activity_dt]
就我而言……使用 MySQL:
SELECT ... GROUP BY TIMESTAMPADD(HOUR, HOUR(columName), DATE(columName))
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