hive的union問題

内容來源：

在hive上執行查詢：

select count(*) from user_active_vv_20110801_31 where

active_type_3>0 

union all 

active_type_7>0 

active_type_9>0 

active_type_11>0 

active_type_12>0 

active_type_17>0 

active_type_22>0; 

報錯：

failed: error in semantic analysis: top level union

is not supported currently; use a subquery for the union 

原來hive不支援頂層union，隻能将union封裝在子查詢中；且必須為union的查詢輸出定義别名，正确的hql如下：

select * from (select count(*) as type3 from

user_active_vv_20110801_31 where

user_active_vv_20110801_31.active_type_3>0 

select count(*) as type3 from

user_active_vv_20110801_31  where

user_active_vv_20110801_31.active_type_7>0 

select count(*) as type3 from user_active_vv_20110801_31

where user_active_vv_20110801_31.active_type_9>0 

where user_active_vv_20110801_31.active_type_11>0 

where user_active_vv_20110801_31.active_type_12>0 

where user_active_vv_20110801_31.active_type_17>0 

where user_active_vv_20110801_31.active_type_22>0) tmp; 

執行結果如下：

54211920 

57691832 

41080830 

44067696 

32052350 

34341676 

13968539