Is there a way to check for Duplicates when Importing Excel Sheet into MySQL table using vb.net

I have a upload excel file on my web application. When the file is uploaded it is supposed to be openned and then import the data into a mysql table. It works fine in that it adds the information just fine. However there is a problem the code I cannot get the duplicate checking to work correctly.. Part of this is because the excel sheet that will be used does not have any column that I can use as a unique identifier. Several times in the excel sheet the information is completely identical across the entire row with only differences in one or two columns... I was thinking I could do something like: Select * FROM table_name WHERE table_col_1 = variable and table_col_2 = variable 2 and etc...

I am thinking by doing this I could compare the values of every column in the row to the import value and if its the same it would skip it... However I cant quite get my head around it... Maybe I am thinking into it to deep and there is a simple way to do this. Below is the function that i am using:

            Private Function PerFormUpdate(ByVal customer As String, ByVal bill_to As String, ByVal Contact As String, ByVal Company As String, ByVal firstName As String, ByVal mi As String, ByVal lastname As String, ByVal phone As String, ByVal altPhone As String, ByVal fax As String)
        Dim _db As New schoolEntities

        Dim command As MySqlCommand = _dbconn.CreateCommand()
        command.Parameters.AddWithValue("@Customer", customer)
        command.Parameters.AddWithValue("@Bill_to", bill_to)
        command.Parameters.AddWithValue("@Contact", Contact)
        command.Parameters.AddWithValue("@Company", Company)
        command.Parameters.AddWithValue("@First_Name", firstName)
        command.Parameters.AddWithValue("@M_I", mi)
        command.Parameters.AddWithValue("@Last_Name", lastname)
        command.Parameters.AddWithValue("@Phone", phone)
        command.Parameters.AddWithValue("@Alt_Phone", altPhone)
        command.Parameters.AddWithValue("@Fax", fax)

        command.CommandText = "SELECT * FROM quickbooks_imports WHERE Customer=@Customer, Bill_to=@Bill_to, Contact=@Contact, Company =@Company, First_Name=@First_Name, M_I=@M_I,  Last_Name=@Last_Name, Phone =@Phone, Alt_Phone=@Alt_Phone, Fax=@Fax"

        _dbconn.Open()

        Dim _mysqlReader As MySqlDataReader = command.ExecuteReader()
        _dbconn.Close()

        If Not _mysqlReader.HasRows Then
            Dim _UpdateItem As New quickbooks_imports
            Dim updateCommand As MySqlCommand = _dbconn.CreateCommand()

            _UpdateItem.Customer = customer
            _UpdateItem.Bill_to = bill_to
            _UpdateItem.Contact = Contact
            _UpdateItem.Company = Company
            _UpdateItem.First_Name = firstName
            _UpdateItem.M_I = mi
            _UpdateItem.Last_Name = lastname
            _UpdateItem.Phone = phone
            _UpdateItem.Alt_Phone = altPhone
            _UpdateItem.Fax = fax

            updateCommand.CommandText = "INSERT INTO quickbooks_imports (Customer,Bill_to,Contact,Company,First_Name,M_I,Last_Name,Phone,Alt_Phone,Fax) VALUES (@Customer, @Bill_to, @Contact, @Company, @First_Name, @M_I, @Last_Name, @Phone, @Alt_Phone, @Fax)"
            updateCommand.Parameters.AddWithValue("@Customer", _UpdateItem.Customer)
            updateCommand.Parameters.AddWithValue("@Bill_to", _UpdateItem.Bill_to)
            updateCommand.Parameters.AddWithValue("@Contact", _UpdateItem.Contact)
            updateCommand.Parameters.AddWithValue("@Company", _UpdateItem.Company)
            updateCommand.Parameters.AddWithValue("@First_Name", _UpdateItem.First_Name)
            updateCommand.Parameters.AddWithValue("@M_I", _UpdateItem.M_I)
            updateCommand.Parameters.AddWithValue("@Last_Name", _UpdateItem.Last_Name)
            updateCommand.Parameters.AddWithValue("@Phone", _UpdateItem.Phone)
            updateCommand.Parameters.AddWithValue("@Alt_Phone", _UpdateItem.Alt_Phone)
            updateCommand.Parameters.AddWithValue("@Fax", _UpdateItem.Fax)



            'updateCommand.CommandText = "INSERT INTO EXCEL (id,Customer,Bill_to,Contact,Company,First_Name,M_I,Last_Name,Phone,Alt_Phone,Fax) VALUES ('" & _UpdateItem.id & "','" & _UpdateItem.Customer & "','" & _UpdateItem.Bill_to & "','" & _UpdateItem.Contact & "','" & _UpdateItem.开发者_开发知识库Company & "','" & _UpdateItem.First_Name & "','" & _UpdateItem.M_I & "','" & _UpdateItem.Last_Name & "','" & _UpdateItem.Phone & "','" & _UpdateItem.Alt_Phone & "','" & _UpdateItem.Fax & "') ON DUPLICATE KEY UPDATE Customer= '" & _UpdateItem.Customer & "' Bill_to= '" & _UpdateItem.Bill_to & "' Contact= '" & _UpdateItem.Contact & "' Company= '" & _UpdateItem.Company & "' First_Name= '" & _UpdateItem.First_Name & "' M_I= '" & _UpdateItem.M_I & "' Last_Name= '" & _UpdateItem.Last_Name & "' Phone= '" & _UpdateItem.Phone & "' Alt_Phone= '" & _UpdateItem.Alt_Phone & "' Fax= '" & _UpdateItem.Fax & "'"
            'updateCommand.CommandText = "INSERT INTO quickbooks_imports (Customer,Bill_to,Contact,Company,First_Name,M_I,Last_Name,Phone,Alt_Phone,Fax) VALUES ('" & _UpdateItem.Customer & "','" & _UpdateItem.Bill_to & "','" & _UpdateItem.Contact & "','" & _UpdateItem.Company & "','" & _UpdateItem.First_Name & "','" & _UpdateItem.M_I & "','" & _UpdateItem.Last_Name & "','" & _UpdateItem.Phone & "','" & _UpdateItem.Alt_Phone & "','" & _UpdateItem.Fax & "') "
            _dbconn.Open()
            Try
                updateCommand.ExecuteNonQuery()
            Catch ex As Exception
                Dim _error As String = Nothing
                MsgBox(ex.Message)
            End Try


            _db.SaveChanges()
        Else
            Dim _NewItem As New quickbooks_imports
            _NewItem.Customer = customer
            _NewItem.Bill_to = bill_to
            _NewItem.Contact = Contact
            _NewItem.Company = Company
            _NewItem.First_Name = firstName
            _NewItem.M_I = mi
            _NewItem.Last_Name = lastname
            _NewItem.Phone = phone
            _NewItem.Alt_Phone = altPhone
            _NewItem.Fax = fax
            _db.quickbooks_imports.AddObject(_NewItem)
            _db.SaveChanges()
        End If
        _dbconn.Close()
        Return View()
    End Function

Any help would be greatly appreciated...

Try to insert data from the excel into another (maybe temporary table), then copy data you need from additional table to the target table, e.g. -

INSERT INTO table1 SELECT DISTINCT * FROM temp_table;

declare @tempExist varchar(50);
set @tempExist=null;

select @tempExist=[ColumnName1] from [TableName]
where [ColumnName1]=@ColumnName1 or [ColumnName2]= @ColumnName2  and so on..

if(@tempExist!=NULL)
Begin
Insert into [TableName] (...)
End

The above code is for mssql.. and some syntax might be wrong.. but that's what I think of..

But this might give u a hint.. good luck!!