QUEL query languages

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QUEL is a relational database query language, based on tuple relational calculus, with some similarities to SQL. It was created as a part of the Ingres DBMS 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 in an implementation called POSTQUEL supported by POSTGRES.^[1] As Oracle and DB2 gained market share in the early 1980s, most companies then supporting QUEL moved to SQL instead.^{[citation needed]} QUEL continues to be available as a part of the Ingres DBMS, although no QUEL-specific language enhancements have been added for many years.^[when?]