สอบถามการ SELECT pro_id ตามปีจาก tb1 แล้วเอา pro_id มาเลือกรวมราคาจาก tb2 ครับ (sql) VB

For i = 2014 To 2050
                sql = "SELECT DISTINCT(YEAR(sale_date)) FROM Sale_head WHERE YEAR(sale_date) =" & i
                command = New SqlCommand(sql, connection)
                Dim y As Integer = command.ExecuteScalar()
                If Not y = Nothing Then
                    sql = "SELECT SUM(sale_net) FROM Sale_head WHERE YEAR(sale_date)='" & y & "'" 'รายรับ
                    command = New SqlCommand(sql, connection)
                    Dim ss As Double = command.ExecuteScalar()

                    sql = "SELECT SUM(buy_cost) FROM Buyproduct WHERE YEAR(buy_date)='" & y & "'" 'รายจ่าย
                    command = New SqlCommand(sql, connection)
                    Dim sb As Double = command.ExecuteScalar()

                    Dim sumsb1 As Double = ss - sb
                    DataGridView1.Rows.Add(New String() {i + 543, ss, sb, sumsb1}) '--เพิ่มรายการที่ละแถว
                End If
            Next

sql = "SELECT distinct(pro_id) FROM Product_return WHERE YEAR(pr_date)='" & y & "'"
                    command = New SqlCommand(sql, connection)
                    selectProid = command.ExecuteReader()
                    While selectProid.Read
                        
                           MessageBox.Show(selectProid(0))
                    End While
                    selectProid.Close()