[FIXED] why do I get Path expected for join when I use join key word in hql

Issue

I have the following HQL

String FIND_PRODUCT_CLASS_ID = "SELECT pc.id FROM ProductClass pc"+ 
" JOIN ProductGroup pg ON pc.id = pg.productClassId" +
" JOIN Product p ON pg.id = p.id" +
" JOIN ProductSub ps ON p.id = ps.productId WHERE ps.id =:childProductSubId";

When I run this query in Spring Hibernate environment, I get the following stack trace.

Caused by: org.hibernate.hql.internal.ast.QuerySyntaxException: Path expected for join! [SELECT pc.id FROM com.xxx.domain.ProductClass pc JOIN ProductGroup pg ON pc.id = pg.productClassId JOIN Product p ON pg.id = p.id JOIN ProductSub ps ON p.id = ps.productId WHERE ps.id =:childProductSubId]
at org.hibernate.hql.internal.ast.QuerySyntaxException.convert(QuerySyntaxException.java:91)
at org.hibernate.hql.internal.ast.ErrorCounter.throwQueryException(ErrorCounter.java:109)
at org.hibernate.hql.internal.ast.QueryTranslatorImpl.analyze(QueryTranslatorImpl.java:284)
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:126)
at org.hibernate.engine.query.spi.HQLQueryPlan.<init>(HQLQueryPlan.java:88)
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:1800)
at org.hibernate.jpa.spi.AbstractEntityManagerImpl.createQuery(AbstractEntityManagerImpl.java:328)
... 146 more

However, if I modifiy the query without join keyword like below, it's succeeded.

String FIND_PRODUCT_CLASS_ID = "SELECT pc.id FROM ProductClass pc, ProductGroup pg, " +
 " Product p, ProductSub ps where pc.id = pg.productClassId "+
 " and pg.id = p.id and p.id = ps.productId and ps.id =:childProductSubId";

I know that I have already found the solution but I'm not sure why it doesn't work with join key word in HQL. Can sombody explain this to me please? Is this something to do with the mapping? In my case objects are mapped in Hibernate layer.

Solution

We need to provide path in HQL query. That's the "Path expected for join" the exception is coming.

change query something like below: Please edit as per use

String FIND_PRODUCT_CLASS_ID = "SELECT pc.id FROM ProductClass pc"+ 
" JOIN pc.ProductGroup pg " +
" JOIN pg.Product p " +
" JOIN p.ProductSub ps WHERE ps.id =:childProductSubId";'

Please refer this.

Answered By - Ankur Singhal