CODEWITHSUNDEEP
mysqlspringhibernatejpa
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Reputation: 1

Spring JPA @Query How to join child and parent tables?

Class Entry {
    int id;
    String name;
}
Class NewEquipment extends Entry{
    int id;
    String name;
    String type;
}
Class Inventory extends Entry{
    int id;
    String name;
    String location;
}

There are three classes and related tables in db, Now I need to have a query like:

 @Query(value = "SELECT ne FROM Entry e INNER JOIN NewEquipment ne WHERE e.id = ne.id")

It throws exception as follows, I don`t know how to join child and parent classes using JPA, I will appreciate any suggestions. Thanks!

Caused by: java.lang.IllegalStateException: No data type for node: org.hibernate.hql.internal.ast.tree.IdentNode 
 \-[IDENT] IdentNode: 'ne' {originalText=ne}
    at org.hibernate.hql.internal.ast.tree.SelectClause.initializeExplicitSelectClause(SelectClause.java:174)
    at org.hibernate.hql.internal.ast.HqlSqlWalker.useSelectClause(HqlSqlWalker.java:937)
    at org.hibernate.hql.internal.ast.HqlSqlWalker.processQuery(HqlSqlWalker.java:705)
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.query(HqlSqlBaseWalker.java:665)
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.selectStatement(HqlSqlBaseWalker.java:301)
    at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.statement(HqlSqlBaseWalker.java:249)
    at org.hibernate.hql.internal.ast.QueryTranslatorImpl.analyze(QueryTranslatorImpl.java:278)
    at org.hibernate.hql.internal.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:206)
    at org.hibernate.hql.internal.ast.QueryTranslatorImpl.compile(QueryTranslatorImpl.java:158)
    at org.hibernate.engine.query.spi.HQLQueryPlan.<init>(HQLQueryPlan.java:131)
    at org.hibernate.engine.query.spi.HQLQueryPlan.<init>(HQLQueryPlan.java:93)
    at org.hibernate.engine.query.spi.QueryPlanCache.getHQLQueryPlan(QueryPlanCache.java:167)
    at org.hibernate.internal.AbstractSessionImpl.getHQLQueryPlan(AbstractSessionImpl.java:301)
    at org.hibernate.internal.AbstractSessionImpl.createQuery(AbstractSessionImpl.java:236)
    at org.hibernate.internal.SessionImpl.createQuery(SessionImpl.java:1836)
    at org.hibernate.jpa.spi.AbstractEntityManagerImpl.createQuery(AbstractEntityManagerImpl.java:328)
    at sun.reflect.GeneratedMethodAccessor71.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at

Upvotes: 0

Views: 871

Answers (1)

Alexander Makarov
Alexander Makarov

Reputation: 886

What's the point of using @Query for this task? You should simply define proper data model, and spring / hibernate will do join tables for you; that's the simple example - https://tenmilesquare.com/spring-boot-jpa-relationship-quick-guide/

Upvotes: 1

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