Date time picker คือว่าจะทำรายงานการขายตามวันที่นะค่ะ แล้วที่นี้ใช้ date time picker

 Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        sqlcon(1) '' ต่อ connection
        sb.Remove(0, sb.Length) '' คำสั่ง Query ข้อมูล
        sb.Append("Select PromotionID ,CreateDate From Promotion")
        sb.Append(" Where  (CreateDate Between '" & DateTimePicker1.Value.ToString("MM/dd/yyy") & "' And '" & DateTimePicker2.Value.ToString("MM/dd/yyy") & "')")
        sql = sb.ToString() '' เก็บใน String 

        pro = Showquerysql(sql, "dtDetailPromotion") '' ยัดข้อมูลเข้า ใน datatable

        With DataGridView1 '' โชว์ข้อมูลใน datagridveiw
            .DataSource = pro
        End With
    End Sub

Option Explicit On
Imports System.Data
Imports System.Data.SqlClient
public class Form1
dim con as sqlconnection
dim com as sqlcommand
dim sb as stringbuilder '' ตรงนี้ครับ
dim dtTable as datatable 
...
...
end class

Option Explicit On
Imports System.Data
Imports System.Data.SqlClient
Module   moduleSql
 Public com As New SqlCommand
 Public con As New SqlConnection
 Public sb As New StringBuilder
 Public dtTabel as Datable
 Public sql As String
...
...
...
end module

Imports System.Data
Imports System.Data.SqlClient
Imports System.Text
Public Class Form2
    Dim dr As SqlDataReader
    Dim cn As SqlConnection
    Dim cm As SqlCommand
    Dim sb As New StringBuilder
    Dim strSql As String
    Dim strCn As String = "Data Source=vss-server;Initial Catalog=Sale;Integrated Security=True"
    Private Sub Form2_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        cn = New SqlConnection()
        With cn
            If .State = ConnectionState.Open Then .Close()
            .ConnectionString = strCn '' string ที่ใช้ต่อ connection
            .Open()
        End With
    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        sb.Remove(0, sb.Length) '' คำสั่ง Query ข้อมูล
        sb.Append("Select PromotionID ,CreateDate From Promotion")
        sb.Append(" Where  (CreateDate Between '" & DateTimePicker1.Value.ToString("MM/dd/yyy") & "' And '" & DateTimePicker2.Value.ToString("MM/dd/yyy") & "')")
        strSql = sb.ToString() '' เก็บใน String 

        com = New SqlCommand()

        With com
            .CommandText = strSql
            .CommandType = CommandType.Text
            .Connection = cn
            dr = .ExecuteReader()
        End With
        If dr.HasRows Then ''check dr
            Dim dtSql As DataTable
            dtSql = New DataTable()
            dtSql.Load(dr)
            With DataGridView1
                .DataSource = dtSql
            End With
        End If
    End Sub
End Class

Imports System.Data
Imports System.Data.SqlClient
Imports System.Text
'Imports System.Windows.Forms
Public Class Form1

    Dim dr As SqlDataReader
    Dim cn As SqlConnection
    Dim cm As SqlCommand
    Dim sb As New StringBuilder
    Dim strSql As String
    Dim strCn As String = "Data Source=bkk314;Initial Catalog=DB_For_Webboard;Integrated Security=True"
    Dim dtTable As DataTable
    Dim Nowdate As Date
    Dim Enddate As Date
 
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        connection()
        sb.Remove(0, sb.Length)
        sb.Append(" SELECT GETDATE() as Gdate") '' get วันที่ปัจจุบัน จาก server
        strSql = sb.ToString
        com = New SqlCommand()
        With com
            .CommandType = CommandType.Text
            .CommandText = strSql
            .Connection = cn
            dr = .ExecuteReader()
        End With
        If dr.HasRows Then
            dtTable = New DataTable
            dtTable.Load(dr)

            Nowdate = CDate(dtTable.Rows(0).Item("Gdate")).ToString("dd/MM/yyyy") '' DateNow
            Enddate = Nowdate.AddDays(7) '' บวกวัน ไปอีก 1 อาทิตย์ เพื่อเทียบวันใกล้หมดอายุ
            '**ถ้าอยู่ในช่วงวันที่ปัจจุบันและนับไปอีก 7 วัน ถือว่าใกล้หมดอายุ
        End If

        connection()
        sb.Remove(0, sb.Length) '' คำสั่ง Query ข้อมูล
        sb.Append("Select productid,productname,price,qty,totalprice,datesales From Product")
        sb.Append(" Where (datesales between '" & Nowdate.ToString("MM/dd/yyy") & "' And ('" & Enddate.ToString("MM/dd/yyy") & "'))")
        strSql = sb.ToString()

        com = New SqlCommand()
        With com
            .CommandType = CommandType.Text
            .CommandText = strSql
            .Connection = cn
            dr = .ExecuteReader()
        End With
        If dr.HasRows Then
            dtTable = New DataTable
            dtTable.Load(dr)
            With DataGridView1
                .DataSource = dtTable
            End With
        End If
    End Sub
    Private Sub connection()
        cn = New SqlConnection()
        With cn
            If .State = ConnectionState.Open Then .Close()
            .ConnectionString = strCn '' string ที่ใช้ต่อ connection
            .Open()
        End With
    End Sub
End Class