title: Same SQL Server 2012 tolerates backward SQL syntax depending on which database is in use?
body: <p>I have encountered a situation where an SQL Server 2012 seems to tolerate SQL syntax e.g. for adding DATETIMEs to DATEs (see <a href="https://stackoverflow.com/questions/18440917/add-datetime-and-time">here</a>) depending on which database is in use.</p>
  
  <p>Could this be the case, and if so what determines the amount of backward compatibility that is tolerated by the same server in such cases. For instance, does it depend on who (which server) originally created the database?</p>