Change format of DateTime value - sql

Question

Everybody seems to hate DateTime values.
In my project, I have a SQL SELECT query to find results in the database matching the parameter values.
The code I have is:
Dim where As String = "WHERE [Supp_Code] = #scode " & _
"AND [DateFrom] = #datfrom " & _
"AND [DateTo] = #datto " & _
"AND [Comm_Code] = #ccode " & _
"AND [Customer_Code] = #custcode "
Dim sql As String = "SELECT [Comm_Code], [AqYear] FROM [Acquisition Commission] "
sql &= where & " ORDER BY [AqYear] ASC"
Dim cmd As New OleDb.OleDbCommand(sql, con)
cmd.Parameters.AddWithValue("#scode", cmbSupp.Text.Trim)
cmd.Parameters.AddWithValue("#datfrom", datFrom.Value)
cmd.Parameters.AddWithValue("#datto", datTo.Value)
cmd.Parameters.AddWithValue("#ccode", txtCommCode.Text)
cmd.Parameters.AddWithValue("#custcode", cmbCustomerCode.Text)
Dim daYear As New OleDb.OleDbDataAdapter(cmd)
Dim dsYear As New DataSet
daYear.Fill(dsYear)
The code itself has no issues. The issue is that the DataSet only ever has 0 rows, because the DateTime format of datFrom.Value (which is a DateTimePicker control) is 'MM/dd/yyyy', but in the database it is stored as 'dd/MM/yyyy'.
What's the easiest way of converting it the correct database format before using it as a parameter?
EDIT
Using the comments/answers below, I've adapted my code to the following:
Dim test As DateTime
Dim test2 As DateTime
test = ugDates.ActiveRow.Cells("DateFrom").Value
test = ugDates.ActiveRow.Cells("DateTo").Value
Try
Dim where As String = "WHERE [Supp_Code] = #scode " & _
"AND [DateFrom] = #datfrom " & _
"AND [DateTo] = #datto " & _
"AND [Comm_Code] = #ccode " & _
"AND [Customer_Code] = #custcode "
Dim sql As String = "SELECT DISTINCT [Comm_Code], [AqYear] FROM [Acquisition Commission] "
sql &= where & " ORDER BY [AqYear] ASC"
Dim cmd As New OleDb.OleDbCommand(sql, con)
cmd.Parameters.Add("#scode", OleDbType.VarChar).Value = cmbSupp.Text
cmd.Parameters.Add(New OleDbParameter("#datfrom", OleDbType.Date).Value = test)
cmd.Parameters.Add(New OleDbParameter("#datto", OleDbType.Date).Value = test2)
cmd.Parameters.Add("#ccode", OleDbType.VarChar).Value = txtCommCode.Text
cmd.Parameters.Add("#custcode", OleDbType.VarChar).Value = cmbCustomerCode.Text
But, it gives me the following error on the second parameter:
The OleDbParameterCollection only accepts non-null OleDbParameter type objects, not Boolean objects.

Answer 1

The issue is that the DataSet only ever has 0 rows, because the DateTime format of datFrom.Value (which is a DateTimePicker control) is 'MM/dd/yyyy', but in the database it is stored as 'dd/MM/yyyy'.
That is probably NOT the issue unless you are storing the date as a string. A date is a structure, not a string, and inherently does not have formatting. Formatting is something that is applied to a string. Its similar to a number like an int or decimal. If this field is indeed a string you should revisit your schema and update the type accordingly.
Most likely you are trying to compare a date with time either in the value of the parameter OR in the value of the query.
Use DateValue function to trim the time of the stored database
Use .Date on the date value to only compare the value date
Code:
Dim where As String = "WHERE [Supp_Code] = #scode " & _
"AND DateValue([DateFrom]) = #datfrom " & _
"AND DateValue([DateTo]) = #datto " & _
"AND [Comm_Code] = #ccode " & _
"AND [Customer_Code] = #custcode "
// select either OleDbType.Date or OleDbType.DBDate
cmd.Parameters.Add(new OleDbParameter("#datfrom", OleDbType.Date) With {.Value = datFrom.Value.Date})
cmd.Parameters.Add(new OleDbParameter("#datto", OleDbType.Date) With {.Value = datTo.Value.Date})
The other possible problem is the logic, why not do a between or range check instead of an equality check on DateFrom and DateTo?
"AND DateValue([DateFrom]) >= #datfrom " & _
"AND DateValue([DateTo]) <= #datto " & _
Ideally you would use the same value here for both #datfrom and #datto. The query above would be any item that has a start/end date that span the passed in date parameter.