@Kenny, is the database you tried your query against set at compatibility level 8.0? If so, you're right that it'll work fine. However, changing the compatibility level to 9.0 (obviously not on a db of any kind of importance if you're changing just to answer a QOTD
), it'll give the error stated as being the correct answer.
Semper in excretia, sumus solum profundum variat