The Domain Relational Calculus is a non-procedural language. It uses mathematical predicate calculus instead of algebra.
The tuple relational calculus is a non-procedural language. A query in the tuple relational calculus is expressed as the set of tuples for which predicate is true.
SQL is a non-procedural Language. It is designed for managing data held in a relational database management system (RDBMS).
PL/SQL is a procedural language designed specifically to embrace SQL statements within its syntax.