Question

我使用java代码tableHiveCell和tableHiveWiFi创建了两个表。

当我尝试按照sql命令运行时：

select count(UEs.cnc) as 'Active UEs' 
                      ^
from 
(select distinct cnc from tableHiveCell wifi  
  union 
 select distinct cnc from tableHiveCell cell)
 as UEs;

我收到错误：

java.sql.SQLException:
Query returned non-zero code: 11,
cause: FAILED: Parse Error: line 1:22 mismatched input 'as' expecting FROM near ')' in from clause
at org.apache.hadoop.hive.jdbc.HiveStatement.executeQuery(HiveStatement.java:189).

我错过了什么吗？

[编辑1]

我试过了：

select count(UEs.cnc) as 'Active UEs' 
                      ^
from 
(select distinct cnc from tableHiveCell wifi)  
  union 
 (select distinct cnc from tableHiveCell cell)
 as UEs;

相同错误

[编辑2]

我试过了：

select count(UEs.cnc) as Active_UEs
 from (select distinct cnc from tableHiveCell wifi
  union ALL 
 select distinct cnc from tableHiveCell cell) as UEs;
                                              ^

获取相同的错误，但上次as：

 line 1:142 mismatched input 'as' expecting Identifier near ')' in subquery source

Answer 1

根据答案表格的要求： Hadoop似乎在子查询上通过AS关键字存在别名问题，您可以轻松地在没有AS关键字的情况下分配别名。

示例可在此处找到：https://www.inkling.com/read/hadoop-definitive-guide-tom-white-3rd/chapter-12/querying-data

引用未来的访问者（请参阅子查询的mt别名）：

SELECT station, year, AVG(max_temperature)
FROM (
  SELECT station, year, MAX(temperature) AS max_temperature
  FROM records2
  WHERE temperature != 9999
    AND (quality = 0 OR quality = 1 OR quality = 4 OR quality = 5 OR quality = 9)
  GROUP BY station, year
) mt
GROUP BY station, year;

运行sql查询Hadoop Java时，从“子句”中获取错误“不匹配的输入'为'期望FROM near'）'

1 个答案: