ACC2000: How to Find Minimum or Maximum Value Across Fields of Record

Advanced: Requires expert coding, interoperability, and multiuser skills.


Summary

Microsoft Access has no built-in functions that find the maximum or minimum values of numbers across the fields of a record. This article provides two custom functions that cycle through the values across fields and return the minimum or maximum values of each record.

More Information

Microsoft provides programming examples for illustration only, without warranty either expressed or implied. This includes, but is not limited to, the implied warranties of merchantability or fitness for a particular purpose. This article assumes that you are familiar with the programming language that is being demonstrated and with the tools that are used to create and to debug procedures. Microsoft support engineers can help explain the functionality of a particular procedure, but they will not modify these examples to provide added functionality or construct procedures to meet your specific requirements. CAUTION: If you follow the steps in this example, you modify the sample database Northwind.mdb. You may want to back up the Northwind.mdb file and follow these steps on a copy of the database.

Follow these steps to create and implement Visual Basic for Applications procedures that find the minimum or maximum values:


  1. Open the sample database Northwind.mdb.
  2. Create a new module and enter the following two functions:
    Function Minimum(ParamArray FieldArray() As Variant)
    ' Declare the two local variables.
    Dim I As Integer
    Dim currentVal As Variant

    ' Set the variable currentVal equal to the array of values.
    currentVal = FieldArray(0)

    ' Cycle through each value from the row to find the smallest.
    For I = 0 To UBound(FieldArray)
    If FieldArray(I) < currentVal Then
    currentVal = FieldArray(I)
    End If
    Next I

    ' Return the minimum value found.
    Minimum = currentVal

    End Function

    Function Maximum(ParamArray FieldArray() As Variant)
    ' Declare the two local variables.
    Dim I As Integer
    Dim currentVal As Variant

    ' Set the variable currentVal equal to the array of values.
    currentVal = FieldArray(0)

    ' Cycle through each value from the row to find the largest.

    For I = 0 To UBound(FieldArray)
    If FieldArray(I) > currentVal Then
    currentVal = FieldArray(I)
    End If
    Next I

    ' Return the maximum value found.
    Maximum = currentVal

    End Function
  3. On the Debug menu, click Compile Northwind.
  4. On the File menu, click Close and Return to Microsoft Access.
  5. Create the following table named tblMinMax:

    Table: tblMinMax
    ---------------------------
    Field Name: Field1
    Data Type: Number
    Field Size: Long Integer

    Field Name: Field2
    Data Type: Number
    Field Size: Long Integer

    Field Name: Field3
    Data Type: Number
    Field Size: Long Integer
  6. Save the table as tblMinMax. When prompted to create a primary key, click No.
  7. Switch the tblMinMax table to Datasheet view and enter the following values:

    Field1 Field2 Field3
    ------ ------ ------
    50 30 40
    40 50 30
    30 40 50
  8. Create a new query based on the tblMinMax table and drag Field1, Field2, and Field3 to the query grid.
  9. In the fourth column of the query grid, enter the following:
    Minimum Value: Minimum([Field1],[Field2],[Field3])
  10. In the fifth column of the query grid, enter the following:
    Maximum Value: Maximum([Field1],[Field2],[Field3])
  11. Run the query. Note that the fourth and fifth columns contain the minimum and maximum values.

References

For more information about creating custom functions, in the Visual Basic Editor, click Microsoft Visual Basic Help on the Help menu, type custom functions in the Office Assistant or the Answer Wizard, and then click Search to view the topic.
Svojstva

ID članka: 209857 - posljednja izmjena: 11. lis 2006. - verzija: 1

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