日期時間組的日期和時間

Question

我有一個名爲activity_dt datetime和數據如下：

2/5/2013 9:24:00 AM 
2/7/2013 7:17:00 AM 

如何通過日期和時間做我組？

Answer 1

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'); 

的MySQL：

SELECT [activity_dt], count(*) 
FROM table1 
GROUP BY hour(activity_dt) , day(activity_dt) 

Answer 2

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] 

Answer 3

使用MySQL，我通常這樣做的：

SELECT count(id), ... 
FROM quote_data 
GROUP BY date_format(your_date_column, '%Y%m%d%H') 
order by your_date_column desc; 

或者在同樣的想法，如果你需要輸出的日期/時間：如果您在日期列指定索引

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; 

中，MySQL應該能夠用它來加快東西小。