Oracle中的时间戳数据类型查询

Question

I have a table called CYCLING_ACCIDENTS_2 containing a TIMESTAMP(6) column called ACC_DATE_TIME , this is an example of how the date is stored 31-MAY-12 16.45.00.000000 , I would like to know how I can query just the time in such a date format so that I can have a time interval for all years I have (2005-2012) but just restricted to certain times in the day. I tried many functions but all I've got so far are syntax errors, I tried to search on the web but I can' t see anything appropriate to my case. Could anyone help?

Thanks!

Answer 1

First of all, a timestamp is a number, not a string. So the date is displayed by default as 31-MAY-12 16.45.00.000000 , but it is actually the amount of microseconds since 1970 I believe.

If you want to select just the time part use to_char()

select to_char(acc_date_time, 'hh24:mi') time
,      count(*) occurences
from   cycling_accidents_2
group by to_char(acc_date_time, 'hh24:mi')

edit : I think this second query actually answers your question:

select *
from   cycling_accidents_2 ca
where  to_char(ca.acc_date_time, 'hh24:mi') between '10:00' and '18:00'
and    ca.acc_date_time >= to_timestamp('01-01-2005', 'dd-mm-yyyy') 
and    ca.acc_date_time < to_timestamp('01-01-2013', 'dd-mm-yyyy')

Answer 2

SELECT * FROM CYCLING_ACCIDENTS_2 WHERE
(EXTRACT(YEAR FROM ACC_DATE_TIME) BETWEEN 2005 AND 2012)
AND
(EXTRACT(HOUR FROM ACC_DATE_TIME) BETWEEN 10 AND 18)