fix(api): 행정구 상위로 검색할 경우 조회 안 되는 오류 수정

src/main/java/com/onebyone/kindergarten/domain/address/repository/SubRegionRepository.java

@@ -1,10 +1,13 @@
 package com.onebyone.kindergarten.domain.address.repository;
 
 import com.onebyone.kindergarten.domain.address.entity.SubRegion;
+import java.util.List;
 import org.springframework.data.jpa.repository.JpaRepository;
 import org.springframework.stereotype.Repository;
 
 @Repository
 public interface SubRegionRepository extends JpaRepository<SubRegion, Long> {
   SubRegion findBySubRegionId(Long subRegionId);
+
+  List<SubRegion> findAllByParent(SubRegion subRegion);
 }

src/main/java/com/onebyone/kindergarten/domain/kindergatens/repository/KindergartenRepository.java

@@ -76,4 +76,12 @@ List<Kindergarten> findNearbyKindergartenEntities(
           + "AND k.subRegionId = :subRegionId")
   List<Kindergarten> findAllByRegionIdAndSubRegionIdWithFetch(
       @Param("regionId") Long regionId, @Param("subRegionId") Long subRegionId);
+
+  @Query(
+      "SELECT k FROM Kindergarten k "
+          + "LEFT JOIN FETCH k.kindergartenWorkReviewAggregate w "
+          + "LEFT JOIN FETCH k.kindergartenInternshipReviewAggregate i "
+          + "WHERE k.regionId = :regionId "
+          + "AND k.subRegionId in :ids")
+  List<Kindergarten> findAllByRegionIdAndSubRegionIdInWithFetch(Long regionId, List<Long> ids);
 }

src/main/java/com/onebyone/kindergarten/domain/kindergatens/service/KindergartenService.java

@@ -151,18 +151,32 @@ public List<KindergartenResponseDTO> getKindergartenByRegion(Long regionId, Long
       throw new BusinessException(ErrorCodes.REGION_NOT_FOUND_EXCEPTION);
     }
 
-    SubRegion subRegion = subRegionRepository.findBySubRegionId(subRegionId);
-
-    if (subRegion == null) {
+    if (subRegionId == null) {
       return kindergartenRepository.findAllByRegionIdWithFetch(regionId).stream()
           .map(KindergartenResponseDTO::from)
           .toList();
     }
+    SubRegion subRegion = subRegionRepository.findBySubRegionId(subRegionId);
+
+    if (subRegion == null) {
+      throw new BusinessException(ErrorCodes.SUB_REGION_NOT_FOUND_EXCEPTION);
+    }
 
     if (!regionId.equals(subRegion.getRegionId())) {
       throw new BusinessException(ErrorCodes.REGION_NOT_MATCHED_WITH_SUB_REGION);
     }
 
+    List<SubRegion> allByParentId = subRegionRepository.findAllByParent(subRegion);
+
+    if (!allByParentId.isEmpty()) {
+      List<Long> ids = allByParentId.stream().map(SubRegion::getSubRegionId).toList();
+      return kindergartenRepository
+          .findAllByRegionIdAndSubRegionIdInWithFetch(regionId, ids)
+          .stream()
+          .map(KindergartenResponseDTO::from)
+          .toList();
+    }
+
     return kindergartenRepository
         .findAllByRegionIdAndSubRegionIdWithFetch(regionId, subRegionId)
         .stream()