I'm a bit of surprised by how shallow people's understanding of database is. Especially for someone have literally wrote thousands of sql queries. The query engine implementation is/should be covered by some extent in any of the database courses, thus I assume anyone with a CS degree shouldn't be surprised that a queries doesn't execute from SELECT(how's that even possible). Perhaps nowadays the major users of SQL don't really have a CS background.
We live in a large N-Dimensional world of knowledge. Everyone at some point is guaranteed to have missed something "they should know", both according to themselves and according to others.
Many times you encounter such knowledge when you are not ready for it, so you forget having encountered it. A good way to convince yourself of this is to start opening up some of your old college text books and look at the chapter introductions and conclusions. You will find some insights that you simply missed regardless of how you performed in the classes.
In my development as a software engineer, there was a noticeable "level up" after 3-4 years where I had accumulated enough knowledge across the various abstraction levels to the point where new concepts integrated cleanly into my mental model of software systems.
During the first few years of exposure to computer science, I definitely lacked the necessary context to understand certain concepts when I encountered them for the first time. For example, I had a theory of computation course that was all about regular expressions, regular languages, context free grammars, etc. At the same time as I took this course, I was also building my first iPhone app, and I often thought "none of this seems applicable". And then two years later I wrote a compiler to implement a subset of Java and I massively reassessed my opinion on the value of understanding the theory of computation and programming languages.
In fairness, you don't need to be a DBA to have written thousands of SQL queries and if you're in your 30s or older it's quite possible you might have forgotten some of the theory since you don't need that level understanding for your day to day.
It's getting on for 20 years since I did CS and I'm certain there's stuff I've forgotten about (I've definitely forgotten half the stuff about network topologies but most of that stuff was about coax networks rather than ethernet so it's not stuff I've much since)
It's fair to forget OSI models since most of programmers don't need to deal with layers below IP, but the fact that there are 3 more hidden layers shouldn't surprise you. As for someone who writes SQL queries for work, I expect some level of understanding of how your underlying system work. Not in great detail, but at least a general picture. I usually consider the desire of understanding an blackbox as an indicator of whether the person will become a great programmer.
I agree with the "blackbox" metaphor 100% but you have to bare in mind that we all have blind-spots. Sometimes they're due to the path we took into our profession, eg different education/training routes; and sometimes due to the way we've specialised, eg the example I'd given about how specialised knowledge that isn't recalled frequently can be forgotten over time. Sometimes it's just because there's so much information to take in that our leaky brains missed that specific detail in lessons. However the fact that the author literally did research that "blackbox" -- hence the article being written -- should be an indicator that she is actually a pretty decent engineer.
I find criticising people for having blind spots that we might consider obvious isn't a great way to share knowledge. Not only does it make individuals less willing to come forward with questions but it also means they're less likely to correct your errors (we are all fallible) for fear of being chastised again.
There are a lot of semi "power users" with little CS background that write simple SQL queries for their work.
I think the main difference is in the level of curiosity/caring the person exhibits when they get a result you don't expect. When they do something that they think should work and it doesn't, do they carefully figure out the system behind it and why?
The users that do will write better queries faster, and the others will will just keep getting frustrated and foist the work onto others.
I got slightly shocked while I do appreciate his curiosity of the db engine and made it to an informative article.
To me, data analytics jobs will be more exposed to non-CS people so SQL will be much more written by non experts. The autonomous database might be the right product towards this future.
I know a lot of healthcare analysts who don't have a proper CS background but MUST use SQL to get data out of govt databases. There's a LOT of inefficient querying going on, and I was definitely guilty of that as a beginner.
