运行 Hive 查询时获取 ParseException

Question

我正在尝试查找工资低于平均工资的员工人数。

我是蜂巢的新手并且有点挣扎，有人可以解释我的陈述有什么问题并帮助我吗？

我的发言-

SELECT COUNT(*) FROM(SELECT wage, AVG(wage) AS avgWage FROM emp_wages) WHERE wage < avgWage;

错误 -

ParseException line 1:82 cannot recognize input near 'where' 'wage' '<' in subquery source

感谢任何帮助！

Answer 1

语法错误。派生 table 应该是别名。

SELECT COUNT(*) 
FROM (SELECT wage, AVG(wage) AS avgWage FROM emp_wages group by wage)  t --alias needed here
WHERE wage < avgWage;

明智的查询，需要更改。

select count(*)
from (SELECT wage, AVG(wage) over() AS avgWage 
      FROM emp_wages
     ) t
where wage < avgWage

Answer 2

问题是 AVG 是一个聚合函数。如果要映射一对多关系，需要使用交叉连接函数：

select 
  count(*), avg(v1.wage),
  sum(case when v.wage < v2.avgwage then 1 else 0 end) below_average
from 
emp_wages v cross join (select avg(wage) as avgwage from emp_wages) as v2

Answer 3

SELECT COUNT(*) 
FROM (SELECT wage, AVG(wage) AS avgWage FROM emp_wages group by wage)avg --group by needed
WHERE wage < avgWage;

Answer 4

正确的查询是：

select count(*) where wage <(select avg(wage) from emp_wages);

您收到解析错误，因为 wage 和 avgWage 在子查询中。

运行 Hive 查询时获取 ParseException

Getting ParseException when running Hive query

hadoop

hive

hql

parseexception