java使用MySQL和HQL数据去重

思路

先查询出知足某种条件的数据的最小ID，而后删除最小ID之外的数据就实现了去重

实例

查询最小ID的重复数据

select * from oms_relation_model orm 
where orm.fd_id=
    (
        select min(t.fd_id) from oms_relation_model t 
            where orm.fd_ekp_id=t.fd_ekp_id and orm.fd_ekp_id=t.fd_ekp_id
    )
;

删除操做

delete from oms_relation_model s 
where s.fd_id not in (
    select orm.fd_id from oms_relation_model orm 
    where orm.fd_id=
        (
            select min(t.fd_id) from oms_relation_model t 
            where orm.fd_ekp_id=t.fd_ekp_id and orm.fd_ekp_id=t.fd_ekp_id
        )
);

HQL

/**
     * 不重复的id列表
     * 
     * @return
     */
    private List<String> getUniqueIds() {
        Session session = getBaseDao().getHibernateSession();
        String sql = "select fdId from OmsRelationModel orm"
                +
                " where orm.fdId in" +
                " (select min(fdId) from OmsRelationModel t where orm.fdEkpId=t.fdEkpId and orm.fdAppPkId=t.fdAppPkId)";
        Query query = session.createQuery(sql);
        List result = query.list();
        logger.info("查询重复数据,list=>" + JSONUtils.valueToString(result));
        return result;
    }

    /**
     * 删除重复的
     * 
     * @param idList
     */
    private void delSame(List idList) {
        Session session = getBaseDao().getHibernateSession();
        String sql = "delete from OmsRelationModel where fdId not in (:ids)";
        Query query = session.createQuery(sql);
        query.setParameterList("ids", idList);
        int result = query.executeUpdate();
        logger.info("查询重复数据,list=>" + JSONUtils.valueToString(result));
        session.flush();
        session.clear();
    }