Форматирование Даты для SQL

Чаще всего:

    SQLDate = Format$(varDate, "\#mm\/dd\/yyyy\#")

По материалам: http://allenbrowne.com/ser-36.html

In VBA code, delimit dates with the "#" symbol. Regardless or your regional settings, Access expects these literal dates to be in the American format, e.g. #12/31/1999#.
To demonstrate this, enter any date in the Criteria row under a date field in Query Design, and then switch to SQL View. In Query Design view, you see the date according to your local settings, but the SQL statement uses mm/dd/yyyy format.
SQL clauses are not always obvious, e.g. the Filter of a form, the WhereCondition of OpenReport, or the third argument of a domain aggregate function. Examples:

    DoCmd.OpenReport "MyReport", acViewPreview, , "InvoiceDate > #12/31/2000#"
    Debug.Print DLookup("StudentID", "tblStudent", "EntryDate = #6/30/1953#")
    strSQL = "SELECT * FROM tblDonation WHERE DonationDate > #" & Format(Me.StartDate, "mm\/dd\/yyyy") & "#;"

The third example demonstrates how to concatenate a date into a SQL string. The Format() function is essential to force the date into American format. Unfortunately, Format() replaces the slashes with the date separator character defined in Control Panel | Regional Settings, so you must specify literal slashes in the format string by preceding the slash with backslashes.
Since this is something you do frequently, you may find it easy to call a small wrapper function for concatenating date strings. The example below formats it as:

Function SQLDate(varDate As Variant) As String
'Purpose:    Return a delimited string in the date format used natively by JET SQL.
'Argument:   A date/time value.
'Note:       Returns just the date format if the argument has no time component,
'                or a date/time format if it does.
'Author:     Allen Browne. allen@allenbrowne.com, June 2006.
    If IsDate(varDate) Then
        If DateValue(varDate) = varDate Then
            SQLDate = Format$(varDate, "\#mm\/dd\/yyyy\#")
        Else
            SQLDate = Format$(varDate, "\#mm\/dd\/yyyy hh\:nn\:ss\#")
        End If
    End If
End Function