Export new data only from Excel to SQL

The following Excel VBA code exports data from a spreadsheet to SQL:

Sub SQLIM()

          ' Send data to SQL Server
     ' This code loads data from an Excel  Worksheet to an SQL Server Table
     ' Data should start in column A and should be in the same order as the server table
     ' Autonumber fields should NOT be included'
     ' FOR THIS CODE TO WORK
     ' In  VBE you need to go Tools  References and check Microsoft Active X Data  Objects 2.x library


    Dim Cn As ADODB.Connection
    Dim ServerName As String
    Dim DatabaseName As String
    Dim TableName As String
    Dim UserID As String
    Dim Password As String
    Dim rs As ADODB.Recordset
    Dim RowCounter As Long
    Dim ColCounter As Integer
    Dim NoOfFields As Integer
    Dim StartRow As Long
    Dim EndRow As Long
    Dim shtSheetToWork As Worksheet
    Set shtSheetToWork = ActiveWorkbook.Worksheets("Sheet1")
    Set rs = New ADODB.Recordset


    ServerName = "WIN764X\sqlexpress" ' Enter your server name here
    DatabaseName = "two28it" ' Enter your  database name here
    TableName = "COS" ' Enter your Table name here
    UserID = "" ' Enter your user ID here
     ' (Leave ID and Password blank if using windows Authentification")
    Password = "" ' Enter your password here
    NoOfFields = 7 ' Enter number of fields to update (eg. columns in your worksheet)
    StartRow = 2 ' Enter row in sheet to start reading  records
    EndRow = shtSheetToWork.Cells(Rows.Count, 1).End(xlUp).Row ' Enter row of last record in sheet

     '  CHANGES
   ' Dim shtSheetToWork As Worksheet开发者_运维问答
   ' Set shtSheetToWork = ActiveWorkbook.Worksheets("Sheet1")
     '********

    Set Cn = New ADODB.Connection
    Cn.Open "Driver={SQL Server};Server=" & ServerName & ";Database=" & DatabaseName & _
    ";Uid=" & UserID & ";Pwd=" & Password & ";"

    rs.Open TableName, Cn, adOpenKeyset, adLockOptimistic

    For RowCounter = StartRow To EndRow
        rs.AddNew
        For ColCounter = 1 To NoOfFields
            rs(ColCounter - 1) = shtSheetToWork.Cells(RowCounter, ColCounter)
        Next ColCounter
    Next RowCounter
    rs.UpdateBatch

     ' Tidy up
    rs.Close
    Set rs = Nothing
    Cn.Close
    Set Cn = Nothing

End Sub

I want to modify the code to:

1. Check if data from column A already exists in the SQL Table.
2. If the data exists, then only update rather than import as a new role.
3. if the data does not exist, then import it as a new role.

This is the wrong way to do this task. Do this from the SQL server instead. Look up the merge command if you are using SQL Server 2008.

Also consider using SSIS to do this task, it is a better choice than doing it from VBA. OR look up the OPenrowset command in t-SQL and do it that way.

I would suggest uploading data from Excel to a staging table in SQL and then call (also via VBA) a SQL stored procedure which contains logic appropriate to your needs to merge the data from the staging table into the ultimate destination table.