For this week’s Query Exercise, your challenge is to find out who keeps messing up the rows in the Users table.

Take any size version of the Stack Overflow database, and the Users table looks like this:

People are complaining that from time to time, the contents of the AboutMe column in some – but not all – of the Users rows are getting mangled. We’re not sure if it’s an app bug, an ETL problem, or someone goofing around in T-SQL, and we need you to find out.

At the same time, this is also a busy production database, and we want to minimize impacts to the end users. The site still needs to go fast.

For this exercise, I’m not expecting a specific “right” or “wrong” answer – instead, for this one, you’re probably going to have a good time sharing your answer in the comments, and comparing your answer to that of others. Feel free to put your queries in a Github Gist, and include that link in your comments. I’ll check back in next week with the approach I usually use with clients. Have fun!