小编use*_*000的帖子

我有三个表:class,student,和teacher

table class
{
    class_id(PK)
}

table student
{
    student_id(PK)
    class_id(PK+FK)
}

table teacher
{
    teacher_id(PK)
    class_id(PK+FK)
}

我在SQL中有一个查询,工作正常.

SELECT data.class_id, count(data.class_id) AS count
FROM ((SELECT class_id FROM student)
        union all
        (SELECT class_id FROM teacher)) AS data
GROUP BY data.user_id
ORDER BY count desc

该查询包含from子句和union操作中的子查询.我无法将其转换为HQL.

请从上面的SQL查询中给我高效的HQL查询.