Hive 配置单元-列级子查询解决方法

我在列级子查询中遇到了问题，假设我想要这样的结果：

select main_table.date,main_table.store,main_table.transaction,yest_table.transaction as yesterday_trans, lw_table.transaction as lastweek_trans, lm_table.transaction as lastmonth_trans
    from
    (select date, store, transaction from table where date=current_date)main_table
    left join
    (select date, store, transaction from table where date=date_sub(current_date,1))yest_table
    on date_sub(main_table.date,1)=yest_table.date and main_table.store=yest_table.store
    left join
    (select date, store, transaction from table where date=date_sub(current_date,7))lw_table
    on date_sub(main_table.date,7)=lw_table.date and main_table.store=yest_table.store
    left join
    (select date, store, transaction from table where date=date_sub(current_date,7))lm_table
    on add_months(current_date,-1)=lm_table.date and main_table.store=yest_table.store

自联接表中包含日期、存储和事务

我知道使用列级子查询使用传统数据仓库是可以实现的，但我发现hive缺少此功能，因此我创建了自己的查询，如下所示：

select main_table.date,main_table.store,main_table.transaction,yest_table.transaction as yesterday_trans, lw_table.transaction as lastweek_trans, lm_table.transaction as lastmonth_trans
    from
    (select date, store, transaction from table where date=current_date)main_table
    left join
    (select date, store, transaction from table where date=date_sub(current_date,1))yest_table
    on date_sub(main_table.date,1)=yest_table.date and main_table.store=yest_table.store
    left join
    (select date, store, transaction from table where date=date_sub(current_date,7))lw_table
    on date_sub(main_table.date,7)=lw_table.date and main_table.store=yest_table.store
    left join
    (select date, store, transaction from table where date=date_sub(current_date,7))lm_table
    on add_months(current_date,-1)=lm_table.date and main_table.store=yest_table.store

对吗？因为我认为可能有更好的解决办法

感谢您

用例+最大聚合：

select main.date,main.store,main.transaction,s.yesterday_trans,s.lastweek_trans,s.lastmonth_trans
    from
    (select date, store, transaction from table where date=current_date)main
    left join
    (select store, 
       max(case when date = date_sub(current_date,1)    then transaction end) yesterday_trans,  
       max(case when date = date_sub(current_date,7)    then transaction end) lastweek_trans,
       max(case when date = add_months(current_date,-1) then transaction end) lastmonth_trans
       from table 
      where date>=add_months(current_date,-1) and date<=date_sub(current_date,1)
      group by store
    ) s on main.store=s.store;

这样，您将消除两个不必要的表扫描和联接。 此解决方案仅适用于当前日期或固定参数，而不是当前日期。如果您想从主表中选择多个日期，那么具有三个按日期连接+存储的解决方案将最有效

嗯，也许，滞后也是一个适用的解决方案

select date,store,transaction,
    case when lag(date,1) over(partition by store order by date) = date_sub(date,1)) --check if LAG(1) is yesterday (previous date)
         then lag(transaction ,1) over(partition by store order by date) = date_sub(current_date,1)) 
    end as yesterday_trans 
...
--where date>=add_months(current_date,-1) and date<=date_sub(current_date,1)

---

如有必要，添加聚合。如果具有滞后的解决方案是适用的，那么它将是最快的，因为它根本不需要连接，并且在一次扫描中完成所有操作。如果您每个日期有许多记录，那么您可能可以在延迟之前预先聚合它们。这不仅适用于当前_日期

预期输出是什么？@TKHN抱歉，我已在条件重复的联接中更新了子查询中的问题BTW，其中筛选器和lm_表子查询中的筛选器错误，应该是date=add_months当前_日期，-1@galih如果不使用如果我们没有当前的_日期，则意味着历史数据..将必须传递参数..？@TKHN则只有原始解决方案适用于具有高基数的COL。是..同意这是一个优化选项..2表扫描将是沉重的操作