antlr.NoViableAltException for子句中带有Querydsl / JPQL / Hibernate的子查询

antlr.NoViableAltException for subquery in then-clause with Querydsl / JPQL / Hibernate

我的应用程序中有三个实体，Customer，PriceLevel和TemporalCustomerPriceLevel。每个客户都有一个名为defaultPriceLevel的字段，该字段直接引用PriceLevel。可以暂时将客户切换到另一个PriceLevel。为此，向TemporalCustomerPriceLevel添加了一个条目，该条目同时引用PriceLevel和客户。

实体类为：

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@Entity
public class Customer implements Serializable {
...
@ManyToOne
@JoinColumn(name ="default_price_level_id")
private PriceLevel defaultPriceLevel;

@OneToMany(mappedBy ="customer", cascade = CascadeType.ALL, orphanRemoval = true)
private List<TemporalCustomerPriceLevel> temporalCustomerPriceLevels
= new ArrayList<TemporalCustomerPriceLevel>();
...
}

@Entity
public class PriceLevel implements Serializable {
...
@OneToMany(mappedBy ="priceLevel", cascade = CascadeType.ALL, orphanRemoval = true)
private List<TemporalCustomerPriceLevel> temporalCustomerPriceLevels;

@OneToMany(mappedBy ="defaultPriceLevel", cascade = CascadeType.PERSIST)
private List<Customer> customers;
...
}

@Entity
public class TemporalCustomerPriceLevel implements Serializable {
...
@ManyToOne
@JoinColumn(name ="customer_id")
private Customer customer;

@ManyToOne(cascade = CascadeType.PERSIST)
@JoinColumn(name ="price_level_id")
private PriceLevel priceLevel;
...
}

我现在要查询有效价格水平，即。 e。如果没有，则为defaultPriceLevel(活动，为简单起见，省略)TemporalCustomerPriceLevel，否则存在TemporalCustomerPriceLevel引用的PriceLevel。

我使用Spring，JPA(休眠)，MySql和Querydsl。在Querydsl中，我编写了以下内容：

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QCustomer customer = QCustomer.customer;
QTemporalCustomerPriceLevel qt = QTemporalCustomerPriceLevel.temporalCustomerPriceLevel;

SimpleExpression<PriceLevel> cases = new CaseBuilder()
.when(JPAExpressions.select(qt.count()).from(qt).where(qt.customer.eq(customer)).eq(1L))
.then(
JPAExpressions.select(qt.priceLevel).from(qt).where(qt.customer.eq(customer))
)
.otherwise(
JPAExpressions.select(customer.defaultPriceLevel).from(customer)
).as("activePriceLevel");

JPAQuery<Tuple> query = factory.select(customer, cases).from(customer);

这会导致错误：

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antlr.NoViableAltException: unexpected AST node: query
at org.hibernate.hql.internal.antlr.HqlSqlBaseWalker.expr(HqlSqlBaseWalker.java:1367) [hibernate-core-4.3.11.Final.jar:4.3.11.Final]
...

Querydsl生成的查询如下所示：

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select customer,
(case when ((select count(temporalCustomerPriceLevel)
from TemporalCustomerPriceLevel temporalCustomerPriceLevel
where temporalCustomerPriceLevel.customer = customer) = ?1)
then (select temporalCustomerPriceLevel.priceLevel
from TemporalCustomerPriceLevel temporalCustomerPriceLevel
where temporalCustomerPriceLevel.customer = customer)
else (select customer.defaultPriceLevel
from Customer customer)
end) as activePriceLevel
from Customer customer

这似乎是有道理的。此外，如果我用固定的PriceLevel对象替换了两个JPAExpressions行，查询将按预期运行。

因此，主要问题是：在case块的then子句中使用子查询是否有任何约束？我的Querydsl有什么问题吗？任何帮助都非常感谢。

我已经解决了以下替代查询可以解决我的问题。不过，如果有人知道当时的休眠和JPQL子查询，我仍然会感兴趣。

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JPAQueryFactory factory = new JPAQueryFactory(em);
QCustomer customer = QCustomer.customer;
QPriceLevel priceLevel = QPriceLevel.priceLevel;
QTemporalCustomerPriceLevel tmp = new QTemporalCustomerPriceLevel("tmp_qtcpl");
Date now = new Date();

JPAQuery<Tuple> query = factory.select(customer, priceLevel).from(customer, priceLevel).where(
JPAExpressions.select(tmp).from(tmp)
.where(tmp.validAfter.loe(now)
.and(tmp.validUntil.after(now)
.and(tmp.priceLevel.eq(priceLevel)
.and(tmp.customer.eq(customer))))).exists()
.or(
customer.defaultPriceLevel.eq(priceLevel)
.and(
JPAExpressions.select(tmp).from(tmp)
.where(tmp.validAfter.loe(now)
.and(tmp.validUntil.after(now)
.and(tmp.customer.eq(customer)))).notExists()
)
)
);