The more fundamental you go, the lesser number of things you need to form a "complete set".
Thus, whatever the complete set is for subatomic particles, it will most certainly have lesser members than for the complete set of atoms.
Getting back to my original point, SQL operates at a fundamental enough level that you do not need a great number of "constructs" to create a query that gives you whatever it is that you need.
I'm not saying it's perfect, but was just supplementing the OPs observation that SQL has surprisingly few "constructs".
Thus, whatever the complete set is for subatomic particles, it will most certainly have lesser members than for the complete set of atoms.
Getting back to my original point, SQL operates at a fundamental enough level that you do not need a great number of "constructs" to create a query that gives you whatever it is that you need.
I'm not saying it's perfect, but was just supplementing the OPs observation that SQL has surprisingly few "constructs".