The best thing to do, in most cases, it to avoid any kind of function and any kind of correlated sub-query including Cross Apply. Yeah, I know... I'm going to get the same argument that people make for cursors... sometimes, it's not possible to do otherwise. The problem is, that a lot of folks just don't know what is and what is not possible... 😉
--Jeff Moden
Change is inevitable... Change for the better is not.