Return Random Sampling from Query

  • Thread starter Thread starter QB
  • Start date Start date
Q

QB

If I have a first query that returns 3000 records, is there a way to build a
second query based upon the first to pull a random sampling of say 225
records from it?

QB
 
SELECT TOP 225 *
FROM QueryName
ORDER BY Rnd(IsNull(NumberFieldInQuery)*0+1);

It would work best if NumberFieldInQuery is the primary key field in the
original table. NumberFieldInQuery needs to be a number field.
 
If I have a first query that returns 3000 records, is there a way to build a
second query based upon the first to pull a random sampling of say 225
records from it?

QB
Click to expand...
You can use the Top Values property of a query, with help
from a little VBA. Put this little function into a Module:

Public Function RndNum(vIgnore As Variant) As Double
Static bRnd As Boolean
If Not bRnd Then
'Initialize the random number generator once only
bRnd = True
Randomize
End If
RndNum = Rnd()
End Function

Then add a calculated field to your Query by typing

Shuffle: RndNum([fieldname])

in a vacant Field cell, where [fieldname] is any field in
your table - this forces Access to give a different random
number for each record.

Sort the query by Shuffle, and set its Top Values property
to the number of records you want to see.
 
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