Let's Talk about .. SQL Server 2005-Convert AD to BD

I found the way to convert the AD to BD in the SQL query from http://www.narisa.com/forums/index.php?act=Print&client=printer&f=22&t=21017
[SQL]

convert(varchar(4), year(AD_Date) + 543)
+ '-' +
convert(varchar(2),month(AD_Date))
+ '-' +
convert(varchar(2), day(AD_Date))
as BD_Date,