hadoop - 配置单元错误 : For Exists/Not Exists operator SubQuery must be Correlated

Question

select * from students1;

students1.name  students1.age   students1.gpa
fred    35  1.28
barney  32  2.32
shyam   32  2.32

select * from students2;
students1.name  students1.age
fred    35
barney  32

当我运行这个查询时

select 
name,age from students1
where not exists
(select name,age from students2);

我收到这个波纹管错误

Error while compiling statement: FAILED: SemanticException line 39:22 Invalid SubQuery expression 'age' in definition of SubQuery sq_1 [ exists (select name,age from students2) ] used as sq_1 at Line 3:10: For Exists/Not Exists operator SubQuery must be Correlated.

Answer 1

错误信息很清楚。使用exists/not exists时，子查询应该相关。

select name,age 
from students1 s1
where not exists (select 1
                  from students2 s2
                  where s1.name=s2.name and s1.age=s2.age
                 )