SQL SERVER DATETIME FORMAT

Question

Studying SQL Server there is something I am not sure of:

A datetime field with the value: 2012-02-26 09:34:00.000

If I select out o

Answer 1

case when isdate(inputdate) = 1 
then convert(datetime, cast(inputdate,datetime2), 103)
else
case when isdate(inputdate) = 0 
then convert(datetime, cast(inputdate,datetime2), 103)