我正在尝试使用 join 执行 HQL 删除。搜索后我发现我需要创建一个查询,就像这里建议的那样:
http://dasunhegoda.com/1093-you-cant-specify-target-table-table_name-for-update-in-from-clause/104/
这是我的查询:
dao.executeByHql(
"DELETE FROM FinalGradeResult e WHERE e.id IN "
+ "( SELECT id FROM "
+ "( SELECT x FROM FinalGradeResult x "
+ "where x.student.id = :studentId "
+ " AND x.classDiscipline IN " +
+ "(SELECT cd from ClassDiscipline cd "
+ " where cd.clazz.id = :clazzId ) ) as X )",
new HqlParameter("studentId", student.getId()),
new HqlParameter("clazzId", from.getId()));
但我一直收到这个错误:
org.hibernate.hql.internal.ast.QuerySyntaxException: unexpected token:( near line 1, column 94 [DELETE FROM xxxxxxxxxxxx.entity.FinalGradeResult e WHERE e.id IN ( SELECT id FROM ( SELECT x FROM xxxxxxxxxxxxxxx.entity.FinalGradeResult x where x.student.id = :studentId AND x.classDiscipline IN (SELECT cd from xxxxxxxxxxxxxxxx.entity.ClassDiscipline cd where cd.clazz.id = :clazzId ) ) as X )]
错误指出第二个( 是错误的,紧跟在"SELECT id FROM"之后的那个
编辑 我试过这样,但出现同样的错误:
dao.executeByHql(
"DELETE FROM FinalGradeResult e WHERE e.id IN "
+ "( SELECT id FROM "
+ "( SELECT x FROM FinalGradeResult x "
+ " where x.student.id = :studentId "
+ " AND x.classDiscipline.clazz.id = :clazzId )"
+ " as X )",
编辑 2:由于我在这个问题中发布的链接中描述的问题,这样的查询不起作用:
dao.executeByHql(
"DELETE FROM FinalGradeResult e WHERE e.id IN " + "( SELECT x.id FROM FinalGradeResult as x "
+ " where x.student.id = :studentId " + " AND x.classDiscipline.clazz.id = :clazzId )",
new HqlParameter("studentId", student.getId()), new HqlParameter("clazzId", from.getId()));
错误是:
Caused by: java.sql.SQLException: You can't specify target table 'tb_final_grade_result' for update in FROM clause
解决方案
在尝试了一切之后,我们的结论是:
- 我们不能直接只有一个查询,因为我们不能在 DELETE 上进行联接。
- 我们不能只有 2 个查询(一个子查询),因为我们有一个 MYSQL BUG(在提供的链接中有描述)
- 我们不能有 3 个查询(2 个子查询),因为我们不能在 FROM 子句中有子查询。这就是为什么我们的第二个查询不起作用
(select * from (select ...))
is invalid.
所以我决定使用NativeSQL来解决问题:
dao.executeBySQL(
" delete from tb_final_grade_result where id in "
+ " (select * from ( select finalgrade1_.id from tb_final_grade_result finalgrade1_ cross join tb_class_discipline classdisci2_ "
+ " where finalgrade1_.id_class_discipline=classdisci2_.id and finalgrade1_.id_student= :studentId and classdisci2_.id_class= :clazzId ) as tmp )",
new HqlParameter("studentId", student.getId()), new HqlParameter("clazzId", from.getId()));
特别感谢@scaisEdge
最佳答案
为什么要在要删除的同一个表上使用in (select
?难道不能把条件放在where子句中吗?
DELETE FROM FinalGradeResult e WHERE e.student.id = :studentId " + " AND e.classDiscipline.clazz.id = :clazzId )",
new HqlParameter("studentId", student.getId()), new HqlParameter("clazzId", from.getId()));
此外,我不确定您指的参数 classDiscipline.clazz.id
是什么? classDiscipline
是否是其他实体,其字段名为 clazz
的又是另一个实体?这就是查询似乎在说的内容。
关于java - HQL - 删除并出现 JOIN 错误,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/36363520/