[BE#459] 친구 상세화면 친구의 주간 학습 카테고리 1위

BE/src/mates/mates.service.ts

@@ -46,10 +46,17 @@ export class MatesService {
         date,
       );
     // 랭킹1위 카테고리 조회 로직 - ToDo
+    const following_primary_category =
+      await this.studyLogsService.getPrimaryCategory(
+        following_id,
+        start_date,
+        date,
+      );
+
     return {
       my_daily_data,
       following_daily_data,
-      following_primary_category: null,
+      following_primary_category,
     };
   }
 

BE/src/study-logs/study-logs.service.ts

@@ -132,6 +132,24 @@ export class StudyLogsService {
     return result;
   }
 
+  async getPrimaryCategory(
+    user_id: number,
+    start_date: string,
+    end_date: string,
+  ): Promise<object> {
+    const primary_category = await this.studyLogsRepository.query(
+      `SELECT c.id, c.name, c.color_code, SUM(study_logs.learning_time) as total_time
+       FROM study_logs
+       LEFT JOIN categories c ON study_logs.category_id = c.id
+       WHERE study_logs.user_id = ?
+       AND study_logs.date BETWEEN ? AND ?
+       GROUP BY c.id
+       ORDER BY total_time DESC
+       LIMIT 1`,
+      [user_id, start_date, end_date],
+    );
+    return primary_category[0].name ?? null;
+  }
   async groupByCategory(user_id: number, date: string): Promise<object> {
     const studyLogsByCategory = await this.studyLogsRepository.query(
       `SELECT