> If your devs are in the habit of writing lots of SQL,
> they'll often decide to do things like write one complex
> query to avoid the need for a few trivial queries.
As someone who single-handedly maintains a large codebase and a large database for a large website, I can assure you you've hit the nail on the head but completely missed the point.
Unless you're writing a hello world style to-do list, trivial queries tend to be the vast minority of the application logic needed. Most queries need some degree of tuning, whether that be to pull out specific rows, associate related data, summarise, or sort. Do this right, and you can achieve in a single query what would take multiple, dozens, perhaps hundreds of round trips to the database if written with "trivial" queries.
And let's not forget, it's particularly rare for the "complex" query to be more complex than the application code needed to implement the equivalent task. SQL isn't always beautiful, but it can often express ideas more succinctly than most general purpose languages. One GROUP BY can save you from writing big loops. One INNER JOIN or subquery can save you from subsequent database calls. One HAVING clause can save you pages of twisted logic.
A "complex" query generally avoids the need for a few trivial queries that are comparatively inefficient, both in terms of resources and latency. The goal is to allow the database to do the hard work of extracting every byte you need and nothing else. Databases are good at this shit, and even with a good ORM you're often forced to compromise or maintain two worlds within one app.
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That said, I acknowledge that there are multiple legitimate points of view on this debate. I tend to find that the SQL vs ORM debate tends to fall depending on the sort of code that's being written, and the sort of logic that's needed. Desktop apps tend to suit ORMs more readily than web apps. Smaller and self-contained apps tend to survive ORMs more gracefully than broad-scoped apps.
Nothing can excuse stored procedures though. Useless garbage.