hive left join 字段不一致

两个hive表left join时，由于关联字段类型不同导致的数据错误（bigint、string），结果会多出来一批数据。

select a.id as id1
,b.id as id2
from table1 a
left join table2 b
on a.id = b.id
where a.id = '1257829907772824682'
-- 1257829907772824682  1257829907772824682
-- 1257829907772824682  1257829907772824680

推测原因可能是：因bigint数据长度截断问题导致，将两个末尾不同的id判断相等了！！！

做类型转换即可：

select a.id as id1
,b.id as id2
from table1 b1
left join table2 b2 
on cast(a.id as string) = b.id
where a.id = '1257829907772824682'