SQL query (insert into) in oledb without duplicates in VB.NET

Question

I want the SQL query command (insert into) in oledb without duplicates and is there the best recommendation?.

Thanks jack

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Try
            connectionString = cn
            con = New OleDbConnection(connectionString)
            con.Open()
            Dim sql As String = "INSERT INTO EXAMPLE2 SELECT * FROM EXAMPLE1"
            cmd = New OleDbCommand(sql, con)
            cmd.ExecuteNonQuery()
            MessageBox.Show("Successfully Updated...", "Update")
            con.Close()
            Me.fillDataGridView1()
            Me.fillDataGridView2()
        Catch myerror As OleDbException
            MessageBox.Show("Error: " & myerror.Message)
        Finally
        End Try
    End Sub

Answer 1

I get an answer solution based on the link below (Avoid duplicates in INSERT INTO SELECT query in SQL Server)

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Try
            connectionString = cn
            con = New OleDbConnection(connectionString)
            con.Open()
            Dim sql As String = "INSERT INTO EXAMPLE2 (CODE,NOD,QTY,PRICE) SELECT t1.CODE, t1.NOD,t1.QTY, t1.PRICE FROM EXAMPLE1 t1 WHERE NOT EXISTS(SELECT CODE FROM EXAMPLE2 t2 WHERE t2.CODE = t1.CODE)"
            cmd = New OleDbCommand(sql, con)
            cmd.ExecuteNonQuery()
            MessageBox.Show("Successfully Updated...", "Update")
            con.Close()
            Me.fillDataGridView1()
            Me.fillDataGridView2()
        Catch myerror As OleDbException
            MessageBox.Show("Error: " & myerror.Message)
        Finally
        End Try
    End Sub