Select depends on date VB.NET and SQL Server - sql-server

Question

I want to count the number of PPM orders this month and every month, And this is my code but when I run I get an error
Incorrect syntax near '#'
I need to know generally how to select depending on date, I hate working with date, help me please. Thanks
Dim dtp0 As New DateTimePicker
Dim dtp1 = dtp0.Value
Dim count_m As Integer
Dim cmd1 As New SqlCommand("SELECT count ([id]) FROM [machines] where ppm1 = #" & dtp1.Day & "/" & dtp1.Month & "/" & dtp1.Year & " # and [takhen] is NULL and [irga] is NULL", connsql)
Dim da1 As New SqlDataAdapter(cmd1)
Dim dt1 As New DataTable
da1.Fill(dt1)
If dt1.Rows.Count > 0 Then
connsql.Open()
count_m = Convert.ToInt32(cmd1.ExecuteScalar())
connsql.Close()
Label68.Text = count_m.ToString
End If

Answer 1

I'll provide advice on how to properly use string concatenation to insert a date into SQL code, given that that is the specific question you're asking, but you should absolutely NOT do that. You should ALWAYS use parameters to insert ANY values into SQL code. Here is my own writeup on that.
As for this specific issue, you need to use the correct date format and there's a much easier way to do that than inserting day, month and year separately, e.g.
Dim sql = $"SELECT * FROM MyTable WHERE DateColumn = #{myDTP.Value:M/dd/yyyy}#"
That is using string interpolation, which is the most correct option in the last couple of VB versions. If you're using an older version then you can use String.Format:
Dim sql = String.Format("SELECT * FROM MyTable WHERE DateColumn = #{0:M/dd/yyyy}#", myDTP.Value)
If you wanted to do it wrong then you could use concatenation operators:
Dim sql = "SELECT * FROM MyTable WHERE DateColumn = #" & myDTP.Value.ToString("M/dd/yyyy") & "#"

Answer 2

Simply using parameters to pass a DateTime value will avoid problems with the date string literal and provide many other benefits too.
Code example:
Dim dtp0 As New DateTimePicker
Dim dtp1 = dtp0.Value
Dim count_m As Integer
Dim cmd1 As New SqlCommand("SELECT count ([id]) FROM [machines] where ppm1 = #ppm1 and [takhen] is NULL and [irga] is NULL;", connsql)
Dim param1 As SqlParameter = cmd1.Parameters.Add("#ppm1", SqlDbType.Date)
param1.Value = New DateTime(dtp1.Year, dtp1.Month, dtp1.Day)
Dim da1 As New SqlDataAdapter(cmd1)
Dim dt1 As New DataTable
da1.Fill(dt1)
If dt1.Rows.Count > 0 Then
connsql.Open()
count_m = Convert.ToInt32(cmd1.ExecuteScalar())
connsql.Close()
Label68.Text = count_m.ToString
End If