Unseparated String Format
Microsoft® SQL Server™ 2000 allows you to specify date data as an unseparated string. The date data can be specified with four, six, or eight digits, an empty string, or a time value without a date value.
The SET DATEFORMAT session setting does not apply to all-numeric date entries (numeric entries without separators). Six- or eight-digit strings are always interpreted as ymd. The month and day must always be two digits.
This is the valid unseparated string format:
A string of only four digits is interpreted as the year. The month and date are set to January 1. When specifying only four digits, you must include the century.