Re: sysdate - 90 mins query

sarath kumar wrote:
>
> i hava a table tbl_tmstmp with date and time as 2
> different columns (tm_date number)and tm_time
> varchar2(6).
> select * from tbl_tmstmp;
> tmstmp_id tm_date tm_time
> -------- -------- -------
> 1 20020502 12:30
> 2 20020503 19:30
> 3 20020503 23:30
> 4 20020504 00:30
> 5 20020504 02:30
> 6 20020504 08:30
>
> i have requuirement to pickup the records which are
> sysdate - 90 minutes. Assuming the sysdate is 20020504
> and time is 03:00 AM i need to pick up the first 4
> records.
>
> is it possible without using the UNION as DBAS are
> picky about using UNIONS.
>
> thanks
> Srini.
>

where tm_date >= to_number(to_char(sysdate - 0.0625, 'YYYYMMDD'))   and to_date(to_char(tm_date)||tm_time, 'YYYYMMDDHH24:MI') >= sysdate - 0.0625

Word of explanation : 0.0625 is 90 minutes expressed as a number of days (90 / 1440).
The first condition is somewhat redundant with the second one. However, if tm_date is indexed and you have a huge number of rows, it will allow you to take advantage of the index, contrarily to the second condition, necessary to test the hour:minutes part.

Oh .. not tested ...

-- 
Regards,

Stephane Faroult
Oriole Software
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Author: Stephane Faroult
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