java使用MySQL和HQL數據去重

思路

先查詢出知足某種條件的數據的最小ID，而後刪除最小ID之外的數據就實現了去重

實例

查詢最小ID的重複數據

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
    )
;

刪除操做

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

/**
     * 不重複的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("查詢重複數據,list=>" + JSONUtils.valueToString(result));
        return result;
    }

    /**
     * 刪除重複的
     * 
     * @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("查詢重複數據,list=>" + JSONUtils.valueToString(result));
        session.flush();
        session.clear();
    }