src/main/java/com/moral/service/impl/HistoryServiceImpl.java
@@ -407,7 +407,8 @@ Map<String, Object> map = historyMapper.getAVGValueByMacAndTimeslot(mac, startTime, endTime, timeUnits); Map<String, Object> returnMap = new HashMap<>(); if (ObjectUtils.isEmpty(map) || map.isEmpty()) { returnMap.put("AQI", "N/V"); returnMap.put("AQI", "N/V"); return returnMap; } else { Map<String, Double> AQIMap = new HashMap<>(); for (Map.Entry<String, Object> entry : map.entrySet()) {