hive报错 ParseException line 10:7 missing EOF at 'by' near 'group'

查询：

select a,b,c

  from (select a,b,c
          from (select a,b,c
                  from table) a
         where rno = 1) 

 group by a;

报错：FAILED: ParseException line 10:7 missing EOF at 'by' near 'group'

原因：hive本身缺陷，需要在每个子查询后面加别名。

改正：

select a,b,c

  from (select a,b,c
          from (select a,b,c
                  from table) a
         where rno = 1) tb

 group by a;