Question

I normally do most of this work in Excel 2007, but I do not think excel is the right tool for managing the data that I need to process. So I am trying to convert an excel spreadsheet to an Access 2007 db which I can do with no problem, but before doing anything to the spreadsheet I go through the process of cleaning up the data in it in order to use the resulting information. In excel I use a macro such as the following

Sub deletedExceptions_row()
    Dim i As Long
    Dim ws As Worksheet

    On Error GoTo whoa

    Set ws = Sheets("data") 

    With ws
        For i = .Cells.SpecialCells(xlCellTypeLastCell).Row To 1 Step -1
            If .Cells(i, 3) = "" Or _
              VBA.Left(.Cells(i, 3), 4) = "511-" Or _
              VBA.Left(.Cells(i, 3), 5) = "CARL-" Then
                .Rows(i).Delete
            End If
        Next i
    End With
    Exit Sub
whoa:
    MsgBox "Value of i is " & i
End Sub

to remove unnecessary records in the spreadsheet how would I accomplish the same thing in Access 2007.

The macro is looking for particular parts or rather the first few characters of the record’s 3rd field in order to determine if the whole record needs to be removed (ex. 511-QWTY-SVP or CARL-52589-00). In all there about 180 such character types that affect 1000’s of rows that need to be removed from the spreadsheet, but I would like to replicate that same process in Access 2007, but do not know how.

Thank you all for your assistance with this problem

Answer 1

Within Access you can execute a DELETE statement to discard rows where the value in a field is an empty string (“”) or matches one of your patterns.

DELETE FROM YourTable
WHERE
       YourField = ""
    OR YourField ALike "511-%"
    OR YourField ALike "CARL-%";

With YourField indexed, that pattern matching in the WHERE clause offers a potentially large performance improvement over a query using the Left() function such as your spreadsheet macro used. IOW, the following query would require the db engine to run those Left() expressions on every row of YourTable. But with the query above and YourField indexed, the db engine could simply select the matching rows … which can easily be an order of magnitude faster.

DELETE FROM YourTable
WHERE
       YourField = ""
    OR Left(YourField, 4) = "511-"
    OR Left(YourField, 5) = "CARL-";