Sql query to fetch record datewise and hourwise

Question

I have a table say ABC with column key and date
like
key date
charge 4/11/2009 00:46:20 AM
reload 3/27/2008 12:46:20 AM
auto 3/27/2008 07:46:20 AM
now i want that the count for column key is selected
datewise and hour wise
like for a particular date for hour between
0000-0001
0001-0002
2300-2400
the no of different key column values come
i.e
for date 4.11.09 hour 2300-2400
charge=5
auto=2
reload=8
how could it be acheived
thanks in advance

Answer 1

Ok, if you want to get all the data for one particular day, you need to know that the times in the DATE format run from 00:00:00 to 23:59:59 on one day. Therefore there is no concept of 24:00:00 as a time for today, because that's equivalent to 00:00:00 of tomorrow!
If you do:
select keyword, trunc(transaction_time, 'hh'), count(*)
from   tid_master
where  transaction_time >= to_date('04.11.2009' || ' 0000','mm.dd.yyyy hh24mi')
and    transaction_time < to_date('04.11.2009' || ' 0000','mm.dd.yyyy hh24mi') + 1
group by keyword, trunc(transaction_time, 'hh')Then you get all the results for the 11th April 2009. (Side note: please note that I have specified four digits for the year - this is good practice, as "09" could refer to 1909, 2009, 2109, etc, and the db could potentially pick one that you're not expecting! Always be explicit - dates have four digit years, therefore enter them as four digits. The Y2K bug was not all that long ago!).
You'd do the above with a variable like:
select keyword, trunc(transaction_time, 'hh'), count(*)
from   tid_master
where  transaction_time >= trunc(your_date_variable)
and    transaction_time < trunc(your_date_variable) + 1
group by keyword, trunc(transaction_time, 'hh')If you don't have an index on the transaction_time column, then it's ok to do this:
select keyword, trunc(transaction_time, 'hh'), count(*)
from   tid_master
where  trunc(transaction_time) = trunc(your_date_variable)
group by keyword, trunc(transaction_time, 'hh')You could replace your variable with sysdate etc.