Absolutely not. SQL is a (nearly) full implementation of the relational algebra, plus other non-relational stuff. The only thing it really can't handle is a table with no columns! (I have to fake that)
a table with no columns would have no primary key... doesn't that violate one of the fundamental tenets of the relational model ?
john r pierce, recycling bits in santa cruz
The relational model requires a key, but the key can be empty (no attributes). Such a relation can itself be empty, or it can have a single tuple as its body. The maths requires it, and it works just fine.
Regards
David M Bennett FACS
Andl - A New Database Language - andl.org