Cannot query entities using JOIN

问题:

I am trying to get my head around HQL and run it inside the Persistence window of IntelliJ IDEA.

Here's the thing: I can run simple queries like these:

hql> SELECT offer FROM OfferEntit offer;
hql> SELECT offer FROM OfferEntit offer WHERE offer.id = 1L; 

but if I add something like a JOIN:

hql> SELECT offer FROM OfferEntit offer 
     JOIN offer.owner AS owner WHERE owner.id = 1L;

I get an empty result. Always. No matter what I do. I have no idea why..

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Also

• I checked whether those records exist - yes they do
• I do not get any error logs

回答1:

Can you try with left join or join fetch

SELECT offer FROM OfferEntit offer 
 LEFT JOIN offer.owner AS owner WHERE owner.id = 1L

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SELECT offer FROM OfferEntit offer 
 JOIN FETCH offer.owner AS owner WHERE owner.id = 1L