There's lots of amazing databases around, each has their own quirks and as the gp says it's generally difficult to drop in replacements due to those quirks. There's a few listed in the article for SQL Server I'm sure anyone could easily find where others deviate from the spec too. But anyway getting back to what you said:
> He is giving examples of violating the standard
That's absolutely true and it's something every other RDBMS does.
To various degrees, and there's violating the standard (by adding non-standard construct) and violating the standard (by failing to implement a feature entirely, or implementing it with different syntax or semantics).
http://troels.arvin.dk/db/rdbms/ is generally my go-to page for that stuff as it lists standard solutions (with reference and mention of the features used being optional if applicable) and alternative db-specific solutions (exclusive or inclusive of the database accepting the standard solution). Sadly it is not really up to date, and obviously does not go through the whole standard.