ด่วยช่วยหน่อยครับบ มีโค้ด ที่สามารถตรวจสอบยอดขายรวมของสินค้ารายเดือน มั๊ยครับ

Imports System.Data
Imports MySql.Data.MySqlClient

Public Class frmCheck
    Private Sub frmCheck_Load() Handles MyBase.Load
        con = New MySqlConnection
        If con.State = ConnectionState.Closed Then
            con.Open()
        End If

        For i = 1 To 12
            ComboMonth.Items.Add(MonthName(i))

        Next
        ComboMonth.SelectedIndex =_
        ComboMonth.FindStringExact(Monthame(DateTime.Now.Month))


        Dim y As Integer = DateTime.Now.Year
        ComboYear.Items.Add(y + 543)
        ComboYear.Items.Add((y - 1) + 543)
      
    End Sub
    Public Sub loadfile()
        Dim sqlQuery As String
        sqlQuery = "select ProductID as รหัสสินค้า,Month as เดือน ,Year as ปี,SalePrice as ราคาขาย from Chack"

        Dim sqlAdapter As New MySqlDataAdapter
        Dim sqlCmd As New MySqlCommand
        Dim sqlTable As New DataTable
        'Dim i As Integer

        With sqlCmd
            .CommandText = sqlQuery
            .Connection = con
        End With

        With sqlAdapter
            .SelectCommand = sqlCmd
            .Fill(sqlTable)
        End With

        DataGridView1.DataSource = sqlTable

    End Sub
    Private Sub DataGridView1_CellClick(sender As System.Object, e As System.Windows.Forms.DataGridViewCellEventArgs) Handles DataGridView1.CellClick
        Dim i As Integer
        i = DataGridView1.CurrentRow.Index
        ComboMonth.Text = DataGridView1.Item(0, i).Value
        ComboYear.Text = DataGridView1.Item(1, i).Value

    End Sub
End Class