I love this error. Primarily because it demonstrates two very important things.
1. Errors matter. Make sure when you ask someone for help you give them the exact error and circumstances causing the error.
2. Experience matters. If you’ve been working with database development for a while you can probably pinpoint exactly what’s causing this error just from the error.
When I was handed this error from one of my co-workers I started by telling them exactly what was wrong, and then out of curiosity started a quick poll.
The answer is about as straightforward as it gets, and yet a pretty good percentage of people won’t get it on the first try.