How to add sequenced number based on sorted value in query in Access

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失恋的感觉
失恋的感觉 2021-01-25 22:45

I have a query which returns some values (att1). I would like also to have next to it the values which would represent a sorted order of att1. Somethin

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  • 2021-01-25 22:51

    Assuming a table name of table1, The following should yield the desired result:

    select a.att1, (select count(*) from table1 b where b.att1 <= a.att1) as att2
    from table1 a;
    

    For every record, the query calculates the number of records less than or equal to the current record, which is then output as the sort index.

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  • 2021-01-25 23:09

    I wrote an article on the various methods for this:

    Sequential Rows in Microsoft Access

    In its simplest form:

    SELECT RowNumber(CStr([ID])) AS RowID, *, FROM SomeTable;
    

    using the RowNumber function:

    ' Builds consecutive row numbers in a select, append, or create query
    ' with the option of a initial automatic reset.
    ' Optionally, a grouping key can be passed to reset the row count
    ' for every group key.
    '
    ' 2018-08-23. Gustav Brock, Cactus Data ApS, CPH.
    '
    Public Function RowNumber( _
        ByVal Key As String, _
        Optional ByVal GroupKey As String, _
        Optional ByVal Reset As Boolean) _
        As Long
    
        ' Uncommon character string to assemble GroupKey and Key as a compound key.
        Const KeySeparator      As String = "¤§¤"
        ' Expected error codes to accept.
        Const CannotAddKey      As Long = 457
        Const CannotRemoveKey   As Long = 5
    
        Static Keys             As New Collection
        Static GroupKeys        As New Collection
        Dim Count               As Long
        Dim CompoundKey         As String
    
        On Error GoTo Err_RowNumber
    
        If Reset = True Then
            ' Erase the collection of keys and group key counts.
            Set Keys = Nothing
            Set GroupKeys = Nothing
        Else
            ' Create a compound key to uniquely identify GroupKey and its Key.
            ' Note: If GroupKey is not used, only one element will be added.
            CompoundKey = GroupKey & KeySeparator & Key
            Count = Keys(CompoundKey)
    
            If Count = 0 Then
                ' This record has not been enumerated.
                '
                ' Will either fail if the group key is new, leaving Count as zero,
                ' or retrieve the count of already enumerated records with this group key.
                Count = GroupKeys(GroupKey) + 1
                If Count > 0 Then
                    ' The group key has been recorded.
                    ' Remove it to allow it to be recreated holding the new count.
                    GroupKeys.Remove (GroupKey)
                Else
                    ' This record is the first having this group key.
                    ' Thus, the count is 1.
                    Count = 1
                End If
                ' (Re)create the group key item with the value of the count of keys.
                GroupKeys.Add Count, GroupKey
            End If
            ' Add the key and its enumeration.
            ' This will be:
            '   Using no group key: Relative to the full recordset.
            '   Using a group key:  Relative to the group key.
            ' Will fail if the key already has been created.
            Keys.Add Count, CompoundKey
        End If
    
        ' Return the key value as this is the row counter.
        RowNumber = Count
    
    Exit_RowNumber:
        Exit Function
    
    Err_RowNumber:
        Select Case Err
            Case CannotAddKey
                ' Key is present, thus cannot be added again.
                Resume Next
            Case CannotRemoveKey
                ' GroupKey is not present, thus cannot be removed.
                Resume Next
            Case Else
                ' Some other error. Ignore.
                Resume Exit_RowNumber
        End Select
    End Function
    

    All code is also on GitHub: VBA.RowNumbers

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