Can all SQL queries be represented in Relational Algebra, Domain and Tuple relational calculus

Question

My query includes a having and count or all in. How are these represented in RA/DRC/TRC? Would I have to simplify my SQL query even more? Here is a simplified example:

Answer 1

Relational Division is the answer to your specific example - you don't need an aggregate. Division is part of the algebra.

Your more general question is a complex one because of the problems of determining when any possible SQL result is the same as a relational one. Is a SQL query that returns duplicate rows equivalent to a relational expression that doesn't? Is a SQL query with SQL-style nulls equivalent to any relational expression? How do you express a relational projection over no attributes using only SQL syntax?

I think the only sensible answer is to say that the SQL model and relational one are two quite different and incompatible things. You probably shouldn't go looking too hard for correspondences between them.