JPA子查询失败

Question

有人知道它失败的原因吗？

@Query("SELECT CASE WHEN COUNT(x) > 0 THEN true ELSE false END FROM City a WHERE x.parking= :parking AND x.section= :section AND x.district IN (SELECT uc FROM DistrictCity uc WHERE uc.zone = :zone AND :user IN uc.users)")
Boolean carsExist(String parking, Section section, String zone, User user);
City (class)
String parking
Section section
DistrictCity district
DistrictCity (class)
String Zone
List<User> users (Many to Many relation)

它没有给出语法问题，但它给了我错误"；缺少表达式(ORA-00936("；问题似乎出在：用户in uc.users

Answer 1

我认为最后一位不正确。这应该有效：

SELECT uc FROM DistrictCity uc JOIN uc.users u WHERE uc.zone = :zone AND u = :user

因此，整个查询变成：

@Query("SELECT CASE WHEN COUNT(x) > 0 THEN true ELSE false END FROM City a WHERE x.parking= :parking AND x.section= :section AND x.district IN (SELECT uc FROM DistrictCity uc JOIN uc.users u WHERE uc.zone = :zone AND u = :user)")