дата храниться на SQL сервере в двоичном формате, естественно без всяких разделителей.
Values with the datetime data type are stored internally by Microsoft® SQL Server™ as two 4-byte integers. The first 4 bytes store the number of days before or after the base date, January 1, 1900. The base date is the system’s reference date. Values for datetime earlier than January 1, 1753, are not permitted. The other 4 bytes store the time of day represented as the number of milliseconds after midnight.