Fix sql error in mysql8+

internal/repo/activity_common/activity_repo.go

@@ -88,7 +88,7 @@ func (ar *ActivityRepo) GetActivity(ctx context.Context, session *xorm.Session,
 func (ar *ActivityRepo) GetUserIDObjectIDActivitySum(ctx context.Context, userID, objectID string) (int, error) {
 	sum := &entity.ActivityRankSum{}
 	_, err := ar.data.DB.Table(entity.Activity{}.TableName()).
-		Select("sum(rank) as rank").
+		Select("sum(`rank`) as `rank`").
 		Where("user_id =?", userID).
 		And("object_id = ?", objectID).
 		And("cancelled =0").
@@ -113,7 +113,7 @@ func (ar *ActivityRepo) AddActivity(ctx context.Context, activity *entity.Activi
 func (ar *ActivityRepo) GetUsersWhoHasGainedTheMostReputation(
 	ctx context.Context, startTime, endTime time.Time, limit int) (rankStat []*entity.ActivityUserRankStat, err error) {
 	rankStat = make([]*entity.ActivityUserRankStat, 0)
-	session := ar.data.DB.Select("user_id, SUM(rank) AS rank_amount").Table("activity")
+	session := ar.data.DB.Select("user_id, SUM(`rank`) AS rank_amount").Table("activity")
 	session.Where("has_rank = 1 AND cancelled = 0")
 	session.Where("created_at >= ?", startTime)
 	session.Where("created_at <= ?", endTime)