[Java] [JPA] [JPQL] Parameters example

Parameters.java

// JPA defines named parameters, and positional parameters.

// Named parameters can be specified in JPQL using the syntax :<name>.
Query query = em.createQuery("SELECT e FROM Employee e WHERE e.firstName = :first and e.lastName = :last");
query.setParameter("first", "Bob");
query.setParameter("last", "Smith");
List<Employee> list = query.getResultList();

// Positional parameters can be specified in JPQL using the syntax ? or ?<position>.
// Positional parameters start at position 1 not 0.
Query query = em.createQuery("SELECT e FROM Employee e WHERE e.firstName = ? and e.lastName = ?");
query.setParameter(1, "Bob");
query.setParameter(2, "Smith");
List<Employee> list = query.getResultList();

// --or--

Query query = em.createQuery("SELECT e FROM Employee e WHERE e.firstName = ?2 and e.lastName = ?1");
query.setParameter(2, "Bob");
query.setParameter(1, "Smith");
List<Employee> list = query.getResultList();