将SQL查询重写为HQL [英] rewrite SQL query to HQL

问题描述

我有SQL查询:

SELECT
    tag.id, 
    tag.description, 
    tag.`name`, 
    COUNT(question_has_tag.question_id)
FROM
    question_has_tag
INNER JOIN
    question
ON 
    question.id = question_has_tag.question_id
INNER JOIN
    tag
ON 
    question_has_tag.tag_id = tag.id
GROUP BY
    tag.id

一切正常.但是我需要将其重写为HQL，有人知道吗?我试过了，但是没用:

All works good. But I need to rewrite it to HQL, some one have any idea? I tried this, but it doesn't work:

list = entityManager.createQuery("SELECT " +
            "t.id, " +
            "t.description, " +
            "t.name, " +
            "COUNT(q.id) " +
            "FROM Tag t INNER JOIN Question q ON t.id = q.id " +
            "GROUP BY t.id").getResultList();

对不起，不是所有信息，我有3个表标签，问题和question_has_tag(由hibernate自动创建)标签，并且问题与ManyToMany有关联

Sorry it not all information, I've 3 table tag, question and question_has_tag (auto created by hibernate) tag and question has ManyToMany relations

@ManyToMany(mappedBy = "tags", fetch = FetchType.LAZY)
    private List<Question> questions;

和

@ManyToMany(fetch = FetchType.LAZY)
    @JoinTable(name = "question_has_tag",
        joinColumns = @JoinColumn(name = "question_id"),
        inverseJoinColumns = @JoinColumn(name = "tag_id"))
    private List<Tag> tags;

推荐答案

尝试一下

list = entityManager.createQuery("SELECT " +
            "t.id, " +
            "t.description, " +
            "t.name, " +
            "COUNT(q.id) " +
            "FROM Tag t JOIN t.questions q" +
            "GROUP BY t.id").getResultList();

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