Even there someone needs to read them eventually than just the person who wrote it. Single letter aliases are just evil. In some ways it’s the same as doing: String x = “Hello”

In the case of ETL you should only be referencing those tables a few times because you are integrating them into friendly analytic models. In that case you probably have a lot of columns to wrangle and complex transformation logic. In those cases I prefer to use no alias at all to avoid the scrolling around to get context, even when table names are very long.