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access 2007 randomize

Posted on 2014-07-30
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Last Modified: 2014-08-07
I am trying to create a randomize function in access2007.  I would like to run a query to return 100 rows from my table. I would like query to the table an get a different result set  everytime i run the query.  Help is needed.  I am including the database i have started.
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Question by:centralmike
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Expert Comment

by:aikimark
ID: 40230255
If you add a column to your query, you can simulate randomness via the VB pseudo-random number function, Rnd().  Pass it the row's key value.
Example:
SELECT ID, Rnd([ID]) AS RndSortValue
FROM MyTable
ORDER BY Rnd([ID]);

Open in new window

Be aware that the VB PRNG functions are flawed.  I wrote an analysis in this article:
http:A_11114.html
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Author Comment

by:centralmike
ID: 40230520
The random number columns changes.  But it returns the same 100 rows each time you run the query.
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DatabaseMX (Joe Anderson - Microsoft MVP, Access and Data Platform) earned 500 total points
ID: 40230645
Here is an example that avoids the issue above - which I've used many times:

SELECT TOP 100 tblEmp.EmpID, tblEmp.EmpName
FROM tblEmp
ORDER BY Rnd(Replace(TimeValue(Now()),":","")*[tblEmp].[EmpID]-Now()*[tblEmp].[EmpID]);
mx
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LVL 75
ID: 40230651
Another similar example:

SELECT TOP 10 tblEmp.EmpID, tblEmp.EmpName
FROM tblEmp
ORDER BY Rnd(Int(Now()*[tblEmp].[EmpID])-Now()*[tblEmp].[EmpID]);

mx
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Expert Comment

by:aikimark
ID: 40230728
@mike

Please post 20 of your ID values.  I'm not seeing that behavior with my table/query.
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Expert Comment

by:Gustav Brock
ID: 40231179
You will if you close Access and open it and run the query again.

/gustav
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LVL 75
ID: 40232252
Guaranteed to not be an issue if you include Now() as shown in my examples.
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LVL 49

Expert Comment

by:Gustav Brock
ID: 40232926
Yes, this is a great tip.

/gustav
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