Rows per hour

Question

Dear All,
I have a table with 2 rows and one has varchar type data and the other is the time stamp (04/02/2013 19:44:40).
Now I want to write a query to count number of rows per hour in the table with date ...strcutre is as follows :
ddata varchar2(20)
ddate date with timestamp ;
Require the output as follows :
March 28th 12 AM - 20
March 28th 1 AM - 40
March 28th 2 AM - 40
where March 28th 12 AM is the date with time
and 20 - number of rows in that date and in that hour..
Please advise..

Answer 1

Hi,
936074 wrote:
Dear All,
I have a table with 2 rows and one has varchar type data and the other is the time stamp (04/02/2013 19:44:40).
Now I want to write a query to count number of rows per hour in the table with date ...strcutre is as follows :
Whenever you have a problem, post CREATE TABLE and INSERT statements for a little sample data, and the results you want from that data.
>
ddata varchar2(20)
ddate date with timestamp ;What is this? DATE and TIMESTAMP are 2 different datatypes.
If ddate is a DATE, then it is not a TIMESTAMP.
If ddate is a TIMESTAMP, then it is not a DATE.
Require the output as follows :
March 28th 12 AM - 20
March 28th 1 AM - 40
March 28th 2 AM - 40
where March 28th 12 AM is the date with time
and 20 - number of rows in that date and in that hour..
Please advise..Here's one way:
SELECT    TRUNC (ddate, 'HH')           AS hour
,       COUNT (*)                AS cnt
FROM       table_x
GROUP BY  TRUNC (ddate, 'HH')
ORDER BY  TRUNC (ddate, 'HH')     -- Or hour
;TRUNC (ddate) will return a DATE, regardless of whether ddate is a DATE or a TIMESTAMP.