Merge branch 'y-watanabe' of https://gitea.it-college.co.jp/2026_09_5H_Spring_KIZAKI/ShareBooks_new into h-seya

src/main/java/com/example/demo/repository/SubCategoryRepository.java

@@ -0,0 +1,12 @@
+package com.example.demo.repository;
+import java.util.List;
+
+import org.springframework.data.jpa.repository.JpaRepository;
+
+import com.example.demo.entity.BookSubcategory;
+
+public interface SubCategoryRepository
+        extends JpaRepository<BookSubcategory,Integer> {
+	List<BookSubcategory> findByBookCategory_BookCategoryId(Integer bookCategoryId);
+
+}