Although not recommended, you can explicitly convert numbers to dates.
SQL Engine stores each DATE value as a four-byte integer using the following formula:
(year - 1900) * 10000 + (month * 100) + day
For example, December 31, 1985 would be stored as the integer 851231; July 4, 1776 stored as -1239296; and March 30, 2041 stored as 1410330.
The following table demonstrates how numeric dates are interpreted when inserted into a column. Note the translation of the third date, which was probably intended to be 1990-12-01.
|This numeric value …||Translates to this date value …|
Notice that this formula best fits two-digit dates in the 1900s. Because of the difficulty of using this format outside of the 1900s, dates are best specified as ANSI date literals instead.