如何计算每小时db中的行数？

Question

在表格中有两列：Datestamp，如2012-12-16，类型为date，Timestamp，如12:22:59，类型为time。是否可以使用1 sql获取特定日期每小时的行数？返回时我需要获得24个号码。

Answer 1

这样的事情：

SELECT COUNT(*) FROM your_table 
WHERE `Datestamp` = '2012-12-16' 
GROUP BY HOUR(`Timestamp`)

Answer 2

SELECT datestamp as day, hour(timestamp) as hour, count(*)
FROM your_table
GROUP BY datestamp, hour(timestamp)