I have a sql table with 4 columns (id (char), ref(varchar), received(timestamp), sent(timestamp)). I would like to make a sql query to get the number of references per quarter of an hour according to the received column. I ve been searching some time but haven t find a real solution to do it in a query. Is there someone who has any idea how to do this? Thanks in advance.
仁爱的注意,
汤姆
http://docs.oracle.com/cd/E11882_01/server.112/e26088/forests220.htm#i79761 rel="nofollow">TRUNC 和EXTRACT 组合每四分之一小时的数据:
SELECT date_hour, time_quarter_hour, COUNT(*)
FROM (SELECT TRUNC(your_timestamp, hh24 ) date_hour,
floor(EXTRACT(MINUTE FROM your_timestamp) / 15) time_quarter_hour
FROM your_table)
GROUP BY date_hour, time_quarter_hour
请参阅下面的尝试。 时间戳在这里并不重要, 可以是日期 。
select
trunc(sysdate, hh24 ) + trunc(to_char(sysdate, mi )/15)*15/1440
from dual;
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