Help calculating differences in values based on Date in Access

Posted on 2014-02-22
Last Modified: 2014-02-23
I have a table in access that have ID, Values and Date.  I have sorted the data based on ID and Date.  I want another field that will show the difference between value of previous  date and the current date and so on. Here is my sample data and expected Value in the Difference column
ID      Value      Date      Difference
10024      7      6/10/2013      0
10024      6      6/17/2013      1
10024      6      6/24/2013      0
10024      6      7/1/2013      0
10024      6      7/8/2013      0
10024      6      7/15/2013      0
10024      7      7/22/2013      -1
10024      6      7/29/2013      1
10024      6      8/5/2013      0
10024      6      8/12/2013      0
10024      6      8/19/2013      0
10024      6      8/26/2013      0
10005      9      6/10/2013      0
10005      9      6/17/2013      0
10005      9      6/24/2013      0
10005      9      7/1/2013      0
10005      9      7/8/2013      0
10005      9      7/15/2013      0
10005      9      7/22/2013      0
10005      9      7/29/2013      0
10005      9      8/5/2013      0
10005      9      8/12/2013      0
10005      9      8/19/2013      0
10005      9      8/26/2013      0
Question by:fb1990
  • 4
  • 3
LVL 39

Expert Comment

ID: 39880184
Look at sample. There is NULL value if previous Date is missing, you can use nz function if you like to have 0 in this case

Author Comment

ID: 39880577
Hello als315,

This works, but when I changed the Table1 to reflect my actual table name in my database.  I get a enter parameter for ID and Date.

Can you please explain how to implement this to me?  The actual ID name in my database is cust_id

Please with implementation.

LVL 39

Accepted Solution

als315 earned 250 total points
ID: 39880590
There is nested query in last column. You should change also there Table1 to real name:

SELECT Table1.ID, Table1.Value, Table1.Date, (SELECT TOP 1 [T].[VALUE] FROM Table1 As T
Where (T.ID = Table1.ID AND T.Date < Table1.Date) ORDER BY [T].[Date] DESC)-[Table1].[Value] AS Datep
FROM Table1
ORDER BY Table1.ID DESC , Table1.Date;

I see fields Date and Value in your table - it was not very good idea to use reserved words as a field name.
Ransomware-A Revenue Bonanza for Service Providers

Ransomware – malware that gets on your customers’ computers, encrypts their data, and extorts a hefty ransom for the decryption keys – is a surging new threat.  The purpose of this eBook is to educate the reader about ransomware attacks.


Author Comment

ID: 39880604
Worked like a charm!  Thank you so much!

Author Closing Comment

ID: 39880606
All I have to say is, Thank you!

Author Comment

ID: 39880620
One more question.  How can i populate the blank values with 0 in the Datep field?

Also for some reason my queries are running very slow... Would you have an idea why?
LVL 39

Expert Comment

ID: 39881564
... NZ((SELECT TOP 1 [T].[VALUE] FROM Table1 As T
Where (T.ID = Table1.ID AND T.Date < Table1.Date) ORDER BY [T].[Date] DESC), [Table1].[Value])  - [Table1].[Value] .....

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

Most if not all databases provide tools to filter data; even simple mail-merge programs might offer basic filtering capabilities. This is so important that, although Access has many built-in features to help the user in this task, developers often n…
In the article entitled Working with Objects – Part 1 (, you learned the basics of working with objects, properties, methods, and events. In Work…
Show developers how to use a criteria form to limit the data that appears on an Access report. It is a common requirement that users can specify the criteria for a report at runtime. The easiest way to accomplish this is using a criteria form that a…
Polish reports in Access so they look terrific. Take yourself to another level. Equations, Back Color, Alternate Back Color. Write easy VBA Code. Tighten space to use less pages. Launch report from a menu, considering criteria only when it is filled…

910 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

23 Experts available now in Live!

Get 1:1 Help Now