Hive 嵌套查询左连接

Question

我是 Hive 的新手，我想实现以下查询

   select a.controlid, 
          b.name as campaign, 
          a.controlactivityid as activitysource,
          c.code as  codemyaprc,
          c.label_en as label_en,
          c.label_fr as label_fr
   from bo_h_control.bridgeactivity a 
        join suvh_econtrol.TMP_GPS_REF b ON a.controlcampaignid = 
   b.ps_cam_id
        left join  srv_h_a8460_fpc.activity c 
                   ON a.controlactivityid=c.code 
                      and c.date_creation= select 
   max(date_creation) from srv_h_a8460_fpc.activity

在最后一个左连接之前它工作正常。嵌套查询显然未在 hive 中授权。

我该如何解决这个问题。

Answer 1

使用子查询代替连接table:

 select a.controlid, 
          b.name as campaign, 
          a.controlactivityid as activitysource,
          c.code as  codemyaprc,
          c.label_en as label_en,
          c.label_fr as label_fr
   from bo_h_control.bridgeactivity a 
        join suvh_econtrol.TMP_GPS_REF b ON a.controlcampaignid = 
   b.ps_cam_id
        left join (select c.*, max(date_creation) over() as max_date_creation
                     from srv_h_a8460_fpc.activity c 
                  ) c ON a.controlactivityid=c.code 
                         and c.date_creation=c.max_date_creation

或者最好将最后一个连接条件移动到子查询的 WHERE 子句中：

 select a.controlid, 
          b.name as campaign, 
          a.controlactivityid as activitysource,
          c.code as  codemyaprc,
          c.label_en as label_en,
          c.label_fr as label_fr
   from bo_h_control.bridgeactivity a 
        join suvh_econtrol.TMP_GPS_REF b ON a.controlcampaignid = 
   b.ps_cam_id
        left join (select * from
                   (
                   select c.*, max(date_creation) over() as max_date_creation
                     from srv_h_a8460_fpc.activity c 
                   )c where max_date_creation=date_creation
                  ) c ON a.controlactivityid=c.code

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