How to Get The SQL String from a JPA Query Object

Can I get the SQL string from a JPA Query object?

If you only want to know how your JPQL or Criteria Query gets translated to the SQL dialect of your database you can enable fine grained logging in the persistence xml and then look into your log files.

The property name and value depends on your JPA implementation. Here is an example of the relevant part of persistence.xml for EclipseLink:

<properties>
    <property name="eclipselink.logging.level" value="FINEST"/>
</properties>

How to view the SQL queries issued by JPA?

Logging options are provider-specific. You need to know which JPA implementation do you use.

• Hibernate (see here):

  <property name = "hibernate.show_sql" value = "true" />
  

• EclipseLink (see here):

  <property name="eclipselink.logging.level" value="FINE"/>
  

• OpenJPA (see here):

  <property name="openjpa.Log" value="DefaultLevel=WARN,Runtime=INFO,Tool=INFO,SQL=TRACE"/>
  

• DataNucleus (see here):

  Set the log category DataNucleus.Datastore.Native to a level, like DEBUG.

Find Native SQL Query from TypedQuery

The best way to achieve this was to activate logs, which allowed me to see what a native query looks like.
This was done by setting the following property

<prop key="hibernate.show_sql">true</prop>

If I understand this correctly,this parameter is set in different places, some people set it in their logging properties (remember the syntax is different)
other in their configuration.
In my case this was set in the xml configuration file that deals with the entityManager properties. Hope this helps

JPA: how do you get/print the JPQL query string behind a (typed) query after parameters have been set?

There is no such thing as "the final JPQL that ultimately gets translated to the final SQL". How a JPA implementation generates the SQL is down to it, and parameters in general will never be substituted into any String. SQL is generated from expression trees etc not a String. If you want param values inserting in then do it yourself since it only makes sense to you

JPA Native Query select and cast object

You might want to try one of the following ways:

• Using the method createNativeQuery(sqlString, resultClass)

  Native queries can also be defined dynamically using the EntityManager.createNativeQuery() API.

  String sql = "SELECT USER.* FROM USER_ AS USER WHERE ID = ?";
  
  Query query = em.createNativeQuery(sql, User.class);
  query.setParameter(1, id);
  User user = (User) query.getSingleResult();
  

• Using the annotation @NamedNativeQuery

  Native queries are defined through the @NamedNativeQuery and @NamedNativeQueries
  annotations, or <named-native-query> XML element.

  @NamedNativeQuery(
      name="complexQuery",
      query="SELECT USER.* FROM USER_ AS USER WHERE ID = ?",
      resultClass=User.class
  )
  public class User { ... }
  
  Query query = em.createNamedQuery("complexQuery", User.class);
  query.setParameter(1, id);
  User user = (User) query.getSingleResult();
  

You can read more in the excellent open book Java Persistence (available in PDF).

<sup>───────

NOTE: With regard to use of getSingleResult(), see Why you should never use getSingleResult() in JPA.</sup>

(SOLVE) Springboot JPA complex SQL query with JOIN and return custom object

expecting CLOSE, found 'FROM'

From this error message it's clear that you have a unclosed bracket.

Close the bracket after c.quantity AS quantity and it works.

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