0418

• Z时代
• 2024-01-10
• 分类：综合

mysql查询某字段是null

SELECT * FROM meter WHERE NB_ID IS NULL

Caused by: org.springframework.dao.IncorrectResultSizeDataAccessException: result returns more than one elements; nested exception is javax.persistence.NonUniqueResultException: result returns more than one elements

 public Meter findMeterByMeterUid(String meterUid) {
      if (meterUid == null) {
         return null;
      }
      Meter meter = this.meterDao.findByMeterUid(meterUid);
      return meter != null?this.findMeterById(meter.getMeterId().intValue()):null;
   }

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