mysql 查询时间的问题

如何查询一天的数据分为24小时，目前的数据查出来

select DATE_FORMAT(daytime,'%Y-%m-%d %H时'), Ptype,dinggou,tuiding
from table where daytime > '2008-12-21' and daytime <='2008-12-21 23:59:59'

DATE_FORMAT(daytime,'%Y-%m-%d %H时') Ptype dinggou tuiding
2008-12-21 00时 135000000000000000704 0 1
2008-12-21 08时 135000000000000000704 1 0
2008-12-21 09时 135000000000000000704 1 2
2008-12-21 10时 135000000000000000704 1 0
2008-12-21 11时 135000000000000000704 1 1
2008-12-21 12时 135000000000000000704 1 0
2008-12-21 13时 135000000000000000704 1 1
2008-12-21 14时 135000000000000000704 3 1
2008-12-21 15时 135000000000000000704 2 1
2008-12-21 16时 135000000000000000704 3 2
2008-12-21 17时 135000000000000000704 6 1
2008-12-21 18时 135000000000000000704 2 2
2008-12-21 19时 135000000000000000704 1 0
2008-12-21 21时 135000000000000000704 1 0
2008-12-21 22时 135000000000000000704 1 1
2008-12-21 23时 135000000000000000704 0 1


先实现没有数据的小时数据用0补上，实现0-23小时的数据都有

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SELECT CAST(CONCAT(DATE('2008-12-21 23:59:59'),' 00:00:00') AS DATETIME)
UNION
SELECT CAST(CONCAT(DATE('2008-12-21 23:59:59'),' 00:01:00') AS DATETIME)

or
用一张表保存01－24
再与工作表连接

'2008-12-21 23