Ummm... CONVERT is relatively expensive and so are all of the substrings not to mention the use of a UDF...
SELECT CAST(STUFF(STUFF('200907111400',11,0,':'),9,0,' ') AS DATETIME)
--Jeff Moden
RBAR is pronounced "ree-bar" and is a "Modenism" for Row-By-Agonizing-Row. First step towards the paradigm shift of writing Set Based code: ________Stop thinking about what you want to do to a ROW... think, instead, of what you want to do to a COLUMN.
Change is inevitable... Change for the better is not.