Understanding EclipseLink, 2.7
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About JPQL Queries

The Java Persistence Query Language (JPQL) is the query language defined by JPA. JPQL is similar to SQL, but operates on objects, attributes and relationships instead of tables and columns. JPQL can be used for reading (SELECT), as well as bulk updates (UPDATE) and deletes (DELETE). JPQL can be used in a NamedQuery (through annotations or XML) or in dynamic queries using the EntityManager createQuery() API.

The disadvantage of JPQL is that dynamic queries require performing string concatenations to build queries dynamically from web forms or dynamic content. JPQL is also not checked until runtime, making typographical errors more common. These disadvantages are reduced by using the query Criteria API, described About the Criteria API.

EclipseLink Extensions to JPQL

EclipseLink supports all of the statements and clauses described in "Query Language" in the JPA Specification, including SELECT queries, update and delete statements, WHERE clauses, literal values, and database functions. For more information, see the JPA Specification.


EclipseLink provides many extensions to the standard JPA JPQL. These extensions provide access to additional database features many of which are part of the SQL standard, provide access to native database features and functions, and provide access to EclipseLink specific features.

EclipseLink's JPQL extensions include:

  • Less restrictions than JPQL, allows sub-selects and functions within operations such as LIKE, IN, ORDER BY, constructors, functions etc.

  • Allow != in place of <>

  • FUNCTION operation to call database specific functions

  • TREAT operation to downcast related entities with inheritance

  • OPERATOR operation to call EclipseLink database independent functions

  • SQL operation to mix SQL with JPQL

  • CAST and EXTRACT functions

  • REGEXP function for regular expression querying

  • Usage of sub-selects in the SELECT and FROM clause

  • ON clause support for defining JOIN and LEFT JOIN conditions

  • Joins between independent entities

  • Usage of an alias on a JOIN FETCH

  • COLUMN operation to allow querying on nonmapped columns

  • TABLE operation to allow querying on non mapped tables


  • Usage of object variables in =, <>, IN, IS NULL, and ORDER BY

For descriptions of these extensions, see "EclipseLink Query Language" in Java Persistence API (JPA) Extensions Reference for EclipseLink.

EclipseLink Special Operators in JPQL

EclipseLink defines several special JPQL operators that allow performing database operations that are not possible in basic JPQL. These include:




  • SQL

For descriptions of these operators, see "Special Operators" in Java Persistence API (JPA) Extensions Reference for EclipseLink.