HQL内连接查询，去重

因为查询条件需要对 连接的表中的两个字段 or 条件查询

导致查询出来的记录，有重复

一.

使用 group by 主键（用这种可以 再 SELECT COUNT(*)    进行分页，记录数的统计）

@Override
	public List<Remotecertapplyorder> getOrderList(int userid, String username,Date[] createDates)
	{
		RemotecertapplyorderDao remotecertapplyorderDao =(RemotecertapplyorderDao) dao;
		List<Date> dateValues = new ArrayList<Date>();
		//StringBuffer hql=new StringBuffer("select distinct ro from Remotecertapplyorder ro left join fetch ro.remotecertapplies r where  1=1 ");
		StringBuffer hql=new StringBuffer("select ro from Remotecertapplyorder ro inner join ro.remotecertapplies r where  1=1 ");
		hql.append(" and ro.applicant.id = "+userid);
		if(StringUtils.hasText(username)){
			hql.append(" and ( r.username like '%"+username+"%' or r.invoicename like '%"+username+"%') ");
		}
		if(createDates[0]!=null){
			hql.append(" and ro.createtime >= ? ");
			dateValues.add(createDates[0]);
		}
		if(createDates[1]!=null){
			hql.append(" and ro.createtime <= ? ");
			dateValues.add(createDates[1]);
		}
		hql.append(" group by ro.id order by ro.id ");
		List<Remotecertapplyorder> remotecertapplyorders =
				(List<Remotecertapplyorder>) remotecertapplyorderDao.find(hql.toString(), dateValues.toArray());
		return remotecertapplyorders;
	}

上面查询的count  与实际得到的 list 结果不一致 需要采用子查询

-----》

@Override
	public List<Remotecertapplyorder> getOrderList(int userid, String username,Date[] createDates)
	{
		RemotecertapplyorderDao remotecertapplyorderDao =(RemotecertapplyorderDao) dao;
		List<Date> dateValues = new ArrayList<Date>();
		
		StringBuffer hql=new StringBuffer("from Remotecertapplyorder where id in (select ro.id from Remotecertapplyorder ro left join ro.remotecertapplies r where 1=1 ");
		hql.append(" and ro.applicant.id = "+userid);
		if(StringUtils.hasText(username)){
			hql.append(" and ( r.username like '%"+username+"%' or r.invoicename like '%"+username+"%') ");
		}
		if(createDates[0]!=null){
			hql.append(" and ro.createtime >= ? ");
			dateValues.add(createDates[0]);
		}
		if(createDates[1]!=null){
			hql.append(" and ro.createtime <= ? ");
			dateValues.add(createDates[1]);
		}
		hql.append(" group by ro.id ) order by id ");
		List<Remotecertapplyorder> remotecertapplyorders =
				(List<Remotecertapplyorder>) remotecertapplyorderDao.find(hql.toString(), dateValues.toArray());
		return remotecertapplyorders;
	}

这样 count 与 得到的实际值相同

二.

使用 distinct

public PaginationSupport<Remotecertapplyorder> getorderList(int userid,     //动态查询加分页
			String username, Date beginTime, Date endTime,
			Integer pagesize, Integer currpageno)
	{
		RemotecertapplyorderDao remotecertapplyorderDao=(RemotecertapplyorderDao) dao;
		PaginationSupport<Remotecertapplyorder> result=new PaginationSupport<Remotecertapplyorder>();
		if(currpageno>0)
			result.setCurrPageNo(currpageno);
		if(pagesize>0)
			result.setPageSize(pagesize);
		StringBuffer hql=new StringBuffer("select distinct ro from Remotecertapplyorder ro left join fetch ro.remotecertapplies r "
				+ "where ro.applicant.id = "+userid );
		if(username!=null && username.length()>0)
			hql.append(" and ( r.username like '%"+username+"%' or r.invoicename like '%"+username+"%')");
		if(beginTime!=null)
			hql.append(" and ro.createtime >= '"+beginTime+"' ");
		if(endTime!=null)
			hql.append(" and ro.createtime <= '"+endTime+"' ");
		hql.append(" order by ro.id ");
		int count=remotecertapplyorderDao.getCount(hql.toString());
		result.setTotalCount(count);
		if(count!=0){
			if(result.getTotalPageCount()<currpageno){
				currpageno = result.getTotalPageCount();
				result.setCurrPageNo(currpageno);
			}
			List<Remotecertapplyorder> list=remotecertapplyorderDao.orderByPage(hql.toString(),result.getPageSize(),result.getCurrPageNo());
			result.setItems(list);
		}
		return result;
	}