Ah, I can already tell I'm not going to like this article.
>lack of proper orthogonality — SQL is hard to compose;
Their reasoning: "The difference in structure is large enough to make any sort of source-level query reuse impractical."
This is blatantly false. The second example in the article using the join covers both the single-row and multi-row result cases. Additionally, SQL can be made very reusable and modular using tools like DBT, or within a DB using views or other constructs.
>lack of compactness — SQL is a large language;
It's certainly smaller in the keyword set than almost any other computer language I have used. This is like saying "It's a very cold day in the Sahara desert" when the temperature is 40C/105F.
>lack of consistency — SQL is inconsistent in syntax and semantics;
Is it? Or do people take liberties with their implementations? There is an SQL Standard and Postgres is compliant to it. Other databases not being fully ANSI SQL compliant is the fault of the DB creators, not the fault of SQL.
>poor system cohesion — SQL does not integrate well enough with application languages and protocols.
It is a relational language designed to be used within a relational database. Do the authors also complain that their screwdrivers are very inefficient at cutting meat?
They're onto something with the trickiness of NULL, but there have already been tons and tons of discussions on Hacker News - anyone with database experience, either analytical or transaction, will tell you that imagining a NULL-free world actually creates more problems then it solves.
I found this to be a highly misinformed article, personally; really it's a marketing ploy for their proprietary language. Just like most other "we have our own query language better than SQL" product, it probably isn't.