小弟刚从mybatis转到hibernate，遇到了不少坑，在这里不定期更新。以告慰相同处境的亲。
1、首先hibernate的HQL语法有很多坑，有些在SQL中能执行的语句，在HQL中未必能执行，比如HQL就不支持union操作，可以考虑把你要union的两个查询分开写，然后将结果合起来，传到你要使用union的地方。
2、其次，注意mysql数据库与SqlServer、oracle数据库存在差别的，虽然SQL语法大体差不多，但是在细小的地方还是不同。
比如：MySQL不支持，在增删操作语句中嵌套本表的查询子语句。
delete from table where id in(select id from table where id >10);//会报错啊，兄弟们，提示mysql不支持自身子嵌套。
修改成：
delete from table where id in(select id from (select id from table where id >10) as A);//成功。
3、对于Spring boot+JPA的复杂查询，需要进行如下配置才可以。不然会报如下错误：
| org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'mainApi': Unsatisfied dependency expressed through field 'checkProductStatusService': Error creating bean with name 'checkProductStatusService': Unsatisfied dependency expressed through field 'checkProductRepository': Error creating bean with name 'checkProductStatusRepository': Invocation of init method failed; nested exception is java.lang.IllegalArgumentException: Validation failed for query for method public abstract java.util.List com.mode.repository.CheckProductStatusRepository.findID2()!; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'checkProductStatusRepository': Invocation of init method failed; nested exception is java.lang.IllegalArgumentException: Validation failed for query for method public abstract java.util.List com.mode.repository.CheckProductStatusRepository.findID2()!; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'checkProductStatusService': Unsatisfied dependency expressed through field 'checkProductRepository': Error creating bean with name 'checkProductStatusRepository': Invocation of init method failed; nested exception is java.lang.IllegalArgumentException: Validation failed for query for method public abstract java.util.List com.mode.repository.CheckProductStatusRepository.findID2()!; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'checkProductStatusRepository': Invocation of init method failed; nested exception is java.lang.IllegalArgumentException: Validation failed for query for method public abstract java.util.List com.mode.repository.CheckProductStatusRepository.findID2()! |
以delete为例：
@Transactional
public interface CheckProductStatusRepository extends JpaRepository<CheckProductStatus, Long> {
@Modifying
@Transactional
@Query(value = "delete from check_product_status where id not in (:listParam)", nativeQuery = true)
void deleteCheckProductStatus(@Param("listParam") List<Integer> listParam);
@Query(value = "select id from check_product_status where product_url is not null and product_url <>'' group by product_url", nativeQuery = true)
List<Integer> findID1();
@Query(value = "select id from check_product_status where product_url is null or product_url ='' group by spu", nativeQuery = true)
List<Integer> findID2();
}