Oracle Year/Month/Day Difference between two columns

Posted on 2013-01-11
Last Modified: 2013-01-11
I found this SQL on the web - thanks to whomever wrote it.  But as you can see from my dates, it's not correctly working.  Is it because of leap years?  Any thoughts, comments, direction greatly appreciated.  Thanks.

trunc(months_between(MEETING_DATE,BIRTH)/12) year,
    trunc(mod(months_between(MEETING_DATE,BIRTH),12)) month,
   trunc(sysdate-add_months(BIRTH,trunc(months_between(MEETING_DATE,BIRTH)/12)*12+trunc(mod(months_between(MEETING_DATE,BIRTH),12)))) day
   from ica_data

ID           BIRTH     MEETING_DATE     YEAR      MONTH        DAY
------------------------- --------- --------- ---------- ---------- ----------
8900007      01-JAN-08 29-NOV-12          4         10         71
9560033      11-DEC-11 29-NOV-12          0         11         61
9570904      29-MAR-12 31-OCT-12          0          7         74
9560033      11-DEC-11 29-NOV-12          0         11         61
9560033      11-DEC-11 17-DEC-12          1          0         31
Question by:diannagibbs
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LVL 22

Accepted Solution

Steve Wales earned 500 total points
ID: 38767408
When you're calculating "DAYS", why are you using sysdate as your beginning date for the calculation ?

Try this maybe?

trunc(months_between(MEETING_DATE,BIRTH)/12) year,
    trunc(mod(months_between(MEETING_DATE,BIRTH),12)) month,
   trunc(MEETING_DATE-(add_months(BIRTH,trunc(months_between(MEETING_DATE,BIRTH)/12)*12+trunc(mod(months_between(MEETING_DATE,BIRTH),12))))) day
   from ica_data

I ran the query against your data and get this (which looks better):

        ID BIRTH     MEETING_D       YEAR      MONTH        DAY
---------- --------- --------- ---------- ---------- ----------
   8900007 01-JAN-08 29-NOV-12          4         10         28
   9560033 11-DEC-11 29-NOV-12          0         11         18
   9570904 29-MAR-12 31-OCT-12          0          7          2
   9560033 17-DEC-11 17-DEC-12          1          0          0

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LVL 74

Expert Comment

ID: 38767447
you're using sysdate where you should be using meeting_date
here's a reorganized version that uses the same calculations but hopefully a little easier to read

select id, birth,meeting_date,
       year,month, meeting_date - add_months(birth,12*year+month) day
from (SELECT id,
       TRUNC(MONTHS_BETWEEN(meeting_date, birth) / 12) year,
       TRUNC(MOD(MONTHS_BETWEEN(meeting_date, birth), 12)) month
  FROM ica_data)
LVL 74

Expert Comment

ID: 38767459
oops, slow, same idea different arrangement

Author Comment

ID: 38767556
Oversite on my part - forgot to change that to the meeting date instead of sysdate.  Thanks so much to you both.  Exactly what I was looking for.  Appreciate fast respone.

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