it was an academic relational language which preceded SQL. Quel is much less procedural than SQL. Ingres & the Britten-Lee machine were originally Quel engines. (Definition by Ann Harrison.)

QUEL is a relational database access language, similar in most ways to SQL, but somewhat better arranged and easier to use. It was created as a part of the groundbreaking Ingres effort at University of California, Berkeley, based on Codd's earlier suggested but not implemented Data Sub-Language ALPHA. QUEL was used for a short time in most products based on the freely-available Ingres source code, most notably Informix.