• You're confusing dates with date formats. Since this is a SQL Server forum, let's talk about SQL Server, which stores dates internally as a number (two numbers, maybe - the specifics aren't important). Any way you choose to present a date is just a representation of that number, totally independent of the way it's stored. I'd be surprised if there are any RDBMSs to which that doesn't apply. If you need to interact with any systems or applications that don't support that (that may or may not include Excel), then you can convert to a different format when you do your ETL.

    John