find difference between dates from a column in oracle

Posted on 2016-08-08
Last Modified: 2016-08-09
I have this data
Emp#           eff_dt                type       seq_nbr     Expected column
1234            7/18/2011      HIRE      1                null
1234           11/23/2012      TERM      2                 16
1234           9/8/2014              HIRE      3                 21
1234            8/23/2015      TERM      4                 11

i need to add another column which would give me difference between eff_dt in Months.
Question by:need_solution
  • 3
  • 3
  • 2
  • +1

Expert Comment

by:Abhimanyu Suri
ID: 41747962
Please try this

  SELECT emp#,
         LAG (eff_dt) OVER (PARTITION BY emp# ORDER BY eff_dt),
            eff_date - LAG (eff_dt) OVER (PARTITION BY emp# ORDER BY eff_dt))

example, for below mentioned data :

42927      8/4/2016 2:00:10.724 AM
42934      8/4/2016 9:00:33.372 AM
43030      8/8/2016 9:00:44.225 AM
42852      7/31/2016 11:01:00.293 PM

Query Result

42852      7/31/2016 11:01:00.293 PM            
42927      8/4/2016 2:00:10.724 AM      7/31/2016 11:01:00.293 PM      0.1
42934      8/4/2016 9:00:33.372 AM      8/4/2016 2:00:10.724 AM      0
43030      8/8/2016 9:00:44.225 AM      8/4/2016 9:00:33.372 AM      0.13

NOTE : Don't take it as an as is solution, you may need to handle NULL and tweak it as per other columns in mentioned example.
LVL 32

Expert Comment

ID: 41748761
A couple of modifications to Abhimanyu Suri's solution - MONTHS_BETWEEN requires two parameters and FLOOR rounds down the months to a whole number -
SELECT emp#, eff_dt, type, seq_nbr,
FLOOR(MONTHS_BETWEEN (eff_dt, LAG (eff_dt) OVER (PARTITION BY emp# ORDER BY eff_dt))) expected_column
FROM your_table
ORDER BY emp#;

Expert Comment

by:Abhimanyu Suri
ID: 41748768
Thanks for correctio "awking" it appears '-' got copied over for  ','

Author Comment

ID: 41749133
Thanks much for the solution but the ORacle version we have in our organization does not support LAG() function
PRTG Network Monitor: Intuitive Network Monitoring

Network Monitoring is essential to ensure that computer systems and network devices are running. Use PRTG to monitor LANs, servers, websites, applications and devices, bandwidth, virtual environments, remote systems, IoT, and many more. PRTG is easy to set up & use.


Expert Comment

by:Abhimanyu Suri
ID: 41749219
I have created a script based on dba_hist_snapshot, you will have to introduce partition by clause in dense rank for employee_id and also in where clause a join on employee_id

Hopefully dense_rank will work for you :)

SELECT b.snap_id,
       MONTHS_BETWEEN (b.begin_interval_time, a.begin_interval_time)
  FROM (SELECT snap_id,
               DENSE_RANK () OVER (ORDER BY begin_interval_time) rnk
          FROM dba_hist_snapshot
         WHERE snap_id IN (43012,
                           43037)) b,
       (SELECT snap_id,
               DENSE_RANK () OVER (ORDER BY begin_interval_time) rnk
          FROM dba_hist_snapshot
         WHERE snap_id IN (43012,
                           43037)) a
 WHERE  b.rnk - 1 = a.rnk (+)
 order by 1

Sample data by lag Query
snap_id     begin_interval_time         LAG (begin_interval_time)     DIFF                      
43012       8/7/2016 3:00:46.993 PM            
43020       8/7/2016 11:00:12.383 PM    8/7/2016 3:00:46.993 PM         0    
43028       8/8/2016 7:00:37.560 AM     8/7/2016 11:00:12.383 PM        0.01
43032       8/8/2016 11:00:50.881 AM    8/8/2016 7:00:37.560 AM         0    
43037       8/8/2016 4:00:06.712 PM     8/8/2016 11:00:50.881 AM        0  

Sample data by above mentioned SQL

snap_id  begin_interval_time            LAG (begin_interval_time)     DIFF                              
43012    8/7/2016 3:00:46.993 PM        
43020    8/7/2016 11:00:12.383 PM       07-AUG-16          0
43028    8/8/2016 7:00:37.560 AM        07-AUG-16          0.010
43032    8/8/2016 11:00:50.881 AM       08-AUG-16          0
43037    8/8/2016 4:00:06.712 PM        08-AUG-16          0
LVL 40

Accepted Solution

Sharath earned 500 total points
ID: 41749356
try this.
SELECT t1.*,CAST(MONTHS_BETWEEN(t1.eff_dt, t2.eff_dt) AS INTEGER) Expected_Column
  FROM your_table t1
  LEFT JOIN your_table t2 ON t1.seq_nbr = t2.seq_nbr + 1;

Open in new window

LVL 32

Expert Comment

ID: 41749359
What is your version of Oracle? Whatever version, you can probably get by with row_number() and a self-join-
select h1.emp#, h1.eff_dt, h1.type, h1.seq_nbr,
floor(months_between(h1.eff_dt, h2.eff_dt))
(select emp#, eff_dt, type, seq_nbr,
 row_number() over (partition by emp# order by eff_dt) rn
 from yourtable) h1
left join
(select emp#, eff_dt,
 row_number() over (partition by emp# order by eff_dt) rn
 from yourtable) h2
on h1.emp# = h2.emp#
and h1.rn - 1 = h2.rn
order by emp#, eff_dt;

Author Closing Comment

ID: 41749374
Thank you Sharath, it worked!
LVL 32

Expert Comment

ID: 41749392
That works fine for one emp# but what happens to the seq_nbr when a new emp# is encountered? If it re-increments (similar to row_number) for each emp#, then it should also work.

Featured Post

Is Your Active Directory as Secure as You Think?

More than 75% of all records are compromised because of the loss or theft of a privileged credential. Experts have been exploring Active Directory infrastructure to identify key threats and establish best practices for keeping data safe. Attend this month’s webinar to learn more.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
How to count the number of rows in multiple Oracle Tables 10 60
Oracle TEXT search question 9 45
Oracle Syntax 8 55
Oracle - Create Procedure with Paramater 16 56
Configuring and using Oracle Database Gateway for ODBC Introduction First, a brief summary of what a Database Gateway is.  A Gateway is a set of driver agents and configurations that allow an Oracle database to communicate with other platforms…
From implementing a password expiration date, to datatype conversions and file export options, these are some useful settings I've found in Jasper Server.
This video explains at a high level about the four available data types in Oracle and how dates can be manipulated by the user to get data into and out of the database.
Via a live example, show how to restore a database from backup after a simulated disk failure using RMAN.

930 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

18 Experts available now in Live!

Get 1:1 Help Now