Using trunc as difference measure btwn two dates

Question

I have a SQL query that works smoothly. It takes the difference between sets of dates that are >=0 and <=0. here it is:
SELECT createdate,  id, objid, start_date, end_date
FROM greggs_date, HNEMap
where active =1
and trunc (createdate-start_date) >=0  and trunc (createdate-end_date) <=0;
Problem is I can't output the differences. In MS SQL Server you can show the number of days difference with the datediff function named in the SELECT part of the SQL statement not so with trunc used to get date differences. How can this query be rework to show the actual days of difference between start and end from create date.

Answer 1

Hi,
robleh7 wrote:
I have a SQL query that works smoothly. It takes the difference between sets of dates that are >=0 and <=0. here it is:
SELECT createdate,  id, objid, start_date, end_date
FROM greggs_date, HNEMap
where active =1
and trunc (createdate-start_date) >=0  and trunc (createdate-end_date) <=0;
Problem is I can't output the differences. In MS SQL Server you can show the number of days difference with the datediff function named in the SELECT part of the SQL statement not so with trunc used to get date differences. How can this query be rework to show the actual days of difference between start and end from create date.
Sorry, I don't understand the problem.
TRUNC (createdate - startdate)    is just a NUMBER.  You can display it just like any other NUMBER.
SELECT  k.hiredate                         AS base_date
,       d30.hiredate
,       TRUNC (k.hiredate - d30.hiredate)  AS dif
FROM        scott.emp  k
CROSS JOIN  scott.emp  d30
WHERE   k.ename        = 'KING'
AND     d30.deptno     = 30
Output:
BASE_DATE   HIREDATE           DIF
17-Nov-1981 20-Feb-1981        270
17-Nov-1981 22-Feb-1981        268
17-Nov-1981 28-Sep-1981         50
17-Nov-1981 01-May-1981        200
17-Nov-1981 08-Sep-1981         70
17-Nov-1981 03-Dec-1981        -16
Post a complete test script (including CREATE TABLE and INSERT statements, if needed)  and the results you want from that script.