weixin_45673116的博客

-- 每人的前三次最高消费select *, rank() over (partition by name order by cost desc ) rkfrom business;select *from ( select *, rank() over (partition by name order by cost desc ) rk from business )t1where rk<=3;...

常用日期函数unix_timestamp:返回当前或指定时间的时间戳 select unix_timestamp();select unix_timestamp("2020-10-28",'yyyy-MM-dd');from_unixtime：将时间戳转为日期格式select from_unixtime(1603843200);current_date：当前日期select current_date;current_timestamp：当前的日期加时间select current_t

-- hive中sql执行顺序 -- 1.from -- 2.join on 或 lateral view explode() t_tmp as c_tmp -- 3.where -- 4.group by -- 5.聚合函数 如sum() count(*) -- 6.having -- 7.select 中若包含over（）开窗函数，执行完非开窗函数后select等待执行完开窗函数， -- 然后执行select完，开窗函数通过表数据进行分区和排序，跟select查询中的字段是

<!-- beeline -u jdbc:hive2://hadoop102:10000 -n lv lv为超级代理，代理上层进行hadoop的操作 User: lv is not allowed to impersonate lv (state=,code=0)出错解决方案--><property> <name>hadoop.proxyuser.lv.hosts</name> <value>*</va

[lv@hadoop102 conf]$ schematool -initSchema -dbType mysql -verboseException in thread "main" java.lang.RuntimeException: com.ctc.wstx.exc.WstxParsingException: Illegal processing instruction target ("xml"); xml (case insensitive) is reserved by the specs.