Java 带条件API的Spring数据JPA子查询

我正在尝试创建一个具有规范的动态查询，其中包含两个具有双向关系的实体。这些实体是：

@Entity
@Table("SUPPLIERS")
public class Supplier implements Serializable {

    @Id
    Column("ID")
    private Long id;

    @Id
    Column("COMPANY_ID")
    private Long companyId;
}


@Entity
@Table("EMPLOYEES")
public class Employee implements Serializable {

    @Id
    private Long id;

    @ManyToOne
    @JoinColumns({
        @JoinColumn(name = "FIRM_ID", referencedColumnName = "ID"),
        @JoinColumn(name = "FIRM_COMPANY_ID", referencedColumnName = "COMPANY_ID")
    })
    private Supplier supplier;
}

当我想根据供应商选择员工时

return new Specification<Employee>() {
    @Override
    public Predicate toPredicate(Root<Employee> root, CriteriaQuery<?> query, CriteriaBuilder cb) {

        Long[] supplierCodes = {1L, 2L};

        Subquery<Supplier> supplierBasicSubquery = query.subquery(Supplier.class);
        Root<Supplier> supplierBasicRoot = supplierBasicSubquery.from(Supplier.class);
        Join<Employee, Supplier> sqTfV = root.join("supplier", JoinType.INNER);

        supplierBasicSubquery.select(sqTfV).where(sqTfV.<Long>get("id").in(supplierCodes));


        return root.<Supplier>get("supplier").in(supplierBasicSubquery);
    }
};

如您所见，内部select列被括号包围，这会导致Oracle引发异常：

java.sql.SQLSyntaxErrorException: ORA-00920: invalid relational operator

我如何解决这个问题，有什么建议吗

非常感谢

java.sql.SQLSyntaxErrorException: ORA-00920: invalid relational operator