An alternative to data masking

Dynamic data masking is a neat new feature in recent SQL Server versions that allows you to protect sensitive information from non-privileged users by masking it. But using a brute-force guessing attack, even a non-privileged user can guess the contents of a masked column. And if you’re on SQL Server 2014 or earlier, you won’t have the option of using data masking at all.

Read on to see how you can bypass dynamic data masking, and for an alternative approach that uses SQL Server column-level security instead.

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Prioritizing rows in a union

I just remembered a pretty common data challenge the other day. Suppose you have a number of tables, all with similar information in them. You want to union their contents, but you need to prioritize them, so you want to choose all the rows from table A, then rows from table B that are not included in A, then rows from C that are not included in A or B, and so on.

This is a pretty common use case in data cleansing or data warehousing applications. There are a few different ways to go about this, some more obvious than others.

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